Coffee's hidden health benefits

27:20That polyphenols are used as a direct energy source for microbes to allow them to reproduce and do their thing. And one of their things is to drill into the fibers and extract, again, then nutrients from that and then produce other ones as a byproduct. So it's probably a bit of both. It's going to be a while, I think, before we work out those proportions. And also, generally, most of these work in combinations in teams and guilds. So it's very hard to work out who's doing what. This is quite a rare example where you've got what seems to be nearly a sort of one-to-one type system here. But, of course, coffee isn't one thing.

28:10So I have a simpler question. We're getting into the weeds. No, no, no, no, no, no. It's great. But my simpler question is, does this mean I have to start drinking coffee? No. I think there's other ways you can improve your health. But I think for those people who don't like the caffeine, decaf coffee really should be more of an option. and I think we ought to be exploring other foods and drinks that do contain some of these good things so that your body can still produce this substance like this quinic acid. And I think that's where a lot of these new science takes us. There could well be a way of making a blend of coffee, for example, that you liked, that we changed its taste profile so it was less bitter for you.

29:06or what's interesting i don't think um we've discussed this before but i gave up coffee more than 20 years ago and it was part of dealing with a lot of food intolerances that i got so i was definitely drinking lots of coffee at 21 i i got these food intolerances after i was i was very sick with very sick with mononucleosis glandular fever and a few years after this as part of trying to deal with this i gave up coffee and one of the things i found was that coffee was definitely triggering a whole bunch of digestive problems. And apparently, this is, you know, it's quite common. So I remember it's one of the things that the doctor had talked about trying.

29:41And it's not necessarily the caffeine, actually, because same impact really with decaf. And so this is part of what I gave up along with this whole process of giving up this vast amount of food and ending up on this sort of really miserable, very processed diet. But interestingly, what I did find was I ended up sort of just drinking more tea that pulled up my level of caffeine. And I think I found like a happy meeting, which is there's a lot of caffeine in a coffee. And I actually found that tea was a lower, lower spike. So it's not that I gave it up because I hated the taste, but I am sort of curious.

30:19I think a lot of people listening and saying, do I have to drink coffee for health? Or is this more saying like, actually, you should think about this as a healthy drink, as opposed to the way that people have thought about it before as unhealthy. but it's not saying you have to drink it if you don't want to but it is definitely like contributing to like the way we get fiber and all these positive things or is this like wow this is like a silver bullet if you're not drinking coffee you should really try quite hard because of how good you think it is i think it's nuanced i think i wouldn't want anyone to regularly eat or drink things they didn't like food is to be enjoyed and savored and that is the most important thing.

30:58And everyone has food preferences. And we've done our twin studies to show that some people, you know, have a sensitive palate. They don't like those bitter flavors at all. And genetically, their threshold is very different to someone else. So realize we're all different. Don't start forcing people to do things. But at the same time, this is a health drink. the evidence is really clear that if you can have, you know, you can reduce heart attacks by 25%, you know, that's pretty cool if you can do that. And there's not many other ways, something so simple you can actually achieve that. So I would say to people who haven't had it like you for, you know, 15, 20 years, try it again occasionally, or try different ways of having it.

31:49Or think of all these vitamins, supplements, multivitamins that people take. They don't really like taking them, but they do it because they think they're doing them good, and there's no evidence whatsoever. Here you have, you know, you could take a shot of espresso, and it's, you know, easier to take the most vitamins, and, you know, a couple of those a day, and you're getting huge health benefits. So I think just revisit it and realize that you can overcome these thresholds, these bitterness thresholds by constant use. It'd be harder for you now because you've been off it, but there might be other ways of doing it.

32:26Perhaps, you know, and that spoonful of sugar will probably, the balance would still be positive, you know, maybe not with six sugars, but... Modern coffee in particular has focused on reducing bitterness and improving kind of flavor as a kind of outcome. And I think we see lighter roasted coffees that have less bitterness to them, the way that we prepare coffee. You know, I think really well-made coffee is not that bitter compared to badly made coffee. I think the thing that's notable about humans is that we're pretty blank slates and our preferences are learned. And while we have different perceptions of things like bitterness, when it comes to flavor, if you want to learn to like something, well, you can just choose to learn to like it.

33:05Like you can acquire a taste if you want to. We do it all the time. No one enjoyed their first lager. No one enjoyed their first lager. It's often no one enjoyed their first coffee. But we go back and we choose to acquire tastes. So genetic studies have shown the threshold is there for bitter taste. So if you don't like coffee, you don't often like red wine as much as white wine. You might find broccoli and Brussels sprouts hard to have. And this is more common in females and also dark beers. So they tend to go together, these freeze profiles. But as James was saying, you know, you can get used to it very easily.

33:46And most of us do that as students. We have basically the world's foremost expert on coffee. And we're going to do something fun. Now, just before we do it, could you explain, does the way in which you make your coffee have a big impact on both the taste, but also sort of tying into what Tim is talking about? Does it impact, therefore, the health of these things, the fiber and the polyphenols we've been talking about? Yes. A lot. I mean, taste is the most important thing for someone like me. But yes, if you take some ground coffee and you brew it, you are dissolving things from it. Okay. And a good percentage of coffee is not soluble.

34:23You could brew it forever, keep running water through it in a little drip machine. It would still be there afterwards. It's simply not soluble. And soluble means it dissolves in the water, right? It will dissolve in the water. It's kind of like wood, what is left over, in a simplified way. The good bits are in the bitty bits. Yeah. Yeah, so you can wash out and dissolve into your brew water about 30 % of the grounds. And so if you took 100 grams of ground coffee, brewed it for ages, dried it out afterwards, you'd have 70 grams left. Okay. And the 30 grams max would end up in a cup. Ideally, you don't want 30 % of the coffee.

34:55Some things you just want to leave behind, actually, that don't taste great. Generally, we want between probably 20 % and 23%, 24 % of the coffee dissolved in the cup below. So you want all of it dissolved in. You want to get somehow the good bits, but leave some of the not nice tasting bits. Generally. And there are some very bitter compounds that tend to come out at higher extractions that people don't enjoy. However, if you don't get enough out of the coffee, you tend to get a lot of the acids and not a lot else. And it's a bit like lemon juice rather than lemonade. Like good coffee should have some balanced acidity, give it a kind of freshness to it, add some flavor.

35:31But badly brewed coffee will just be sour, unpleasant, and to be avoided. And so, firstly, you want to get the extraction right for the taste perspective. And that's how finely you grind the coffee. Obviously, the more surface area you expose, the easier it is for the water to get in and pull out the things that you want. Because there's a correlation between what you're extracting in terms of taste and what you're extracting in terms of the soluble fibers and things like the chlorogenic acids, a well-brewed cup of coffee will have more of everything good. More taste, more chlorogenic acids, more polyphenols, therefore, and theoretically a little bit more fiber too.

36:05So all in all, you want to get your money's worth. You've bought some nice coffee. There's good stuff in it. You want to make sure you're getting it all out. So that's the kind of the goal of good coffee brewing. So I understand you have brought along a sort of mini laboratory to show us how both professional, all, we'll sort of test for these compounds, but they can also talk through for us to understand, and we are going to have a sort of tasting and science experiment at the same time. Yeah, I think it's interesting. I have a little portable caffeine meter that has the benefit of also giving me an output of chlorogenic acids present in the brew as well.

36:42It'll be in milligrams per deciliter, so per 100 milliliters. We can scale it up to a normal cup of coffee for people in a minute. But yeah, it'll give you an idea of something like instant coffee versus fresh brewed. What are the differences there? And then we can have a look at instant as well, which is a lot of people's choice, and talk about some of the kind of theoretical benefits that instant might have or might not have. Got it. So we're going to try it. Let's just run through. What are the different things that you're going to brew us up? So I'll make you some regular, fresh, well-grown Arabica coffee.

37:12I've then got some good decaf coffee, and I can talk about decaffeination because I think it's something people want to know more about and sort of fear a little bit because they see chemistry and get a little bit nervous. And then I've got some instant too. And instant's super interesting on a technical level. However you feel about the taste, I'm going to try and stay away from the politics of taste of that. But we can actually look at some of the chemistry of what you get in there or what you don't get in there. Got it. And I think we might have a coffee kombucha as well. Oh, good. All right, James.

37:41So we've got the equipment out, which now looks very impressive. Can you tell me what you've got? Sure. This is called an AeroPress. It was invented by the guy that invented the AeroB. And it's kind of a bit like a French press and a paper filtered brewer all in one. So I'll put ground coffee in, hot water, let them steep together. It's a paper filter at the bottom here and at some point I'll press it and so it'll separate the grounds from the liquid. I will add some coffee, which I ground just before I got in a cab to come here. So it's nice and fresh. And you're just throwing in a random amount of coffee?

38:09I would use as a ratio, 60 grams of coffee per liter of water that I want to brew. So I'm going to brew 20 grams of coffee to 330 mils. And the answer is you very carefully measured the amount of coffee and you're going to put in just the right amount of water is what you're saying. Yeah, it just, I like using weighing scales because most of the time I'm making coffee before I've had coffee and I don't want to guess or have to think. And I like a weighing scale for telling me what I have to do and I just make the number happen. So that's why I'm big on scales. And this is for an Americano? So this will brew like a filter strength brew, yes.

38:42So Americanos tend to be fractionally stronger, but like a drip coffee kind of strength seem to be the easiest thing. And while you're pouring, tell me about the water because one thing that did entertain me is that James arrived with his own water. I don't know how much you want to know about water because it's a miserable subject, but the minerals in water play a big role in extracting the flavours. So they are involved in essentially dissolving some of the stuff that we want. But then there's also something called alkalinity, or a buffer if you want to get into the chemistry, which will affect your perceived acidity.

39:16And too much buffer makes everything taste a bit brown and dull, No buffer makes things taste very sour and unpleasant. So I brought water that had an ideal amount of minerals in terms of calcium and an ideal amount of buffer so that we get some acidity, but not too much. So you won't take the water out of the tap. You have to get your own specially modified water to make the coffee the way you want it to taste. London water tastes good, but it has a lot of calcium and a lot of buffer in it too. So it tends to make all coffee kind of taste a bit the same, which is a bit of a shame. And so I, you know, I've paid for the good stuff.

39:49I want it out and I want to enjoy it as much as possible. Making your own water is a little bit extreme. I agree. I'm glad you're still at the point where you can see a little bit, at least, the entertainment that I'm taking from the fact that you not only brought your own coffee, which seems very reasonable, but brought your own water, which I think is acceptable, but verging on the slightly eccentric. And what about adding salt you mentioned? So, yeah, salt's interesting. Salt's a great little hack in that for the majority of people, it's not everyone, table salt acts as a bitterness suppressor right it's one of the reasons you obviously salt and dark chocolate together actually it makes them more palatable as well as enhancing flavor too but if you are served miserably bitter coffee you know the kind of the real filth in a hotel breakfast kind of coffee a tiny sprinkle of salt and i mean a tiny don't you know just a little tiny sprinkle stir it in you'll be shocked at the it sort of mutes the bitterness quite impressively and increases, let's say, palatability.

40:44When you just need the caffeine, I want to help get you there. This shouldn't need salt, I would hope. And so talk me through. The hot water's been sitting there right now. And you described before about how the fact that the ground coffee has a lot of things inside it which are going to start to dissolve. So is that what is going on right now? That's what's going on right now. So, you know, essentially the water's pulling these things out of the cells that we've sort of exposed through grinding the coffee bean. And so the longer you leave it, the more is being dissolved out. There's a point at which you have diminishing returns, and it's not worth waiting much more.

41:15So I'm just giving a quick mix before I press it down, and then we'll press it through, and we'll have a brew. Now, this is paper filtered. From a health perspective, the data seems to suggest that actually paper filtered is healthier for you than unfiltered. I think it was a big Scandinavian study that showed that the peak heart health benefits came with filtered coffee. I think there's a couple of lipids in coffee that were sort of filtered by paper that show a correlation to an increased rate, sort of level of serum cholesterol. I just enjoy it more, if I'm honest. I enjoy the clarity of flavor that comes with it.

41:46I'm not sure it's that convincing, though, because these are intermediate effects on lipids. And as we're saying, lipids are complicated. So short-term change in lipids doesn't mean necessarily long-term health. So stick with the one you prefer, I think. Now, what I'm going to do is just do a little caffeine test on this, and then I can dispense to you. That looks quite weak to me. It's a light roast. So this is actually from a Scandinavian coffee company, and Scandinavians are famous for their light roasts. But it should have a little bit more fruitiness to it, lower levels of bitterness from being a lighter roast.

42:17So for the I don't like coffee, you could approach this more as like a strange fruit tea mentally and see how you get on with that. I'm very excited. I'm definitely drinking the coffee that has been made in this exquisite fashion. So I'll just give it a quick stir just to get a better sample. And James, you've brought a piece of technology here. Do you want to talk us through, for those people who are just listening on audio, what are you doing? So it's a little Bluetooth-connected caffeine and chlorogenic acids analyzer. What I'll do is I'll pull a very specific quantity of coffee with a little pipette here, and I'll add it to a small solution that I'll shake together for a while.

42:54And then there's a chip that I insert into a machine. I cover a little sensor with the liquid, the reagent and the coffee. And then within about 15 seconds, it'll tell me the caffeine content and the chlorogenic acid content. Which is a sort of polyphenol? So about, I think, 90 % of the polyphenols in coffee are counted as chlorogenic acids. I think there are some others in there, but there's a very strong correlation between the quantity. The basis gives you a measure of the amount of polyphenols. Right, one of the major classes of polyphenols. So there's loads of individual variants within that, but that's like a big category.

43:25How cool. I'm going to have to shake this for 10 seconds. Do you do this every time you go to a coffee shop? No, no, because they're like five for a test. It's very quick. I mean, it's interesting. We did it. We took it to sort of different chains to look at the variants. If you ordered an espresso, what's the caffeine dose going to be and how much is it going to vary? And the answer is massively. And caffeine is one of those things. And as much as it isn't all that coffee is, it is a big part of it, where it's the most popular drug and we consume in a completely unregulated way. If you order a coffee out, you've no idea how much caffeine you're about to consume.

44:00I'm not sure that's good. As much as I like coffee, I'm just not sure that that's a brilliant idea. It's like going to a pub and not knowing what percentage of alcohol is in that beer, isn't it? Absolutely. Any of these coffee shop chains, even in the same machine, same trained staff, will produce a different caffeine. So there's a high degree of variation. It's not like when you're just drinking a beer or something that every glass of beer has the same level of alcohol. No, it's regulated. You've got to show on it how much alcohol is in that bottle. But the amount of caffeine will change a lot.

44:33No, there's no testing in terms of caffeine. Can I send this along to you if you want to have a little taste? Yes, I would love to have a taste. Tell me how I'm supposed to taste my coffee. If you have a glass that is sort of oval-shaped, so to speak, yes, swirling it will give you a kind of nice headspace of aromas that you can smell if you want to do that. You don't have to do that. if you sip it if you slurp when you sip you will generally have a sort of more intense flavor experience as you sort of um spray the coffee around it and send more stuff volatile um like olive oil tasting all anyone wine tasting whiskey everyone likes a slurp what i would say as someone who hasn't drunk coffee for a really long time is smells really nice much less strong than i would normally expect from a coffee and the color also you know tim already sort of um mentioned this It actually looks like it could be a tea.

45:20It's really not that dark. Yeah. So as a brew, this is on the very light, very fruity end. And you might think, oh, there's no caffeine in this then. No. So the caffeine level, we'll start there. That's the easiest thing. Because that's sort of understandable to most people. So that's 72 milligrams per deciliter. So if you drank, let's say, a small, which would be 200 mils, that would be 140-ish, 145 milligrams of caffeine. The daily recommended sort of dosage for adult males is about up to three to 400 milligrams. That's almost half your amount, just in one small cup of coffee. Three smalls over the course of the day would exceed your recommended caffeine dose.

46:00So it's actually surprisingly caffeinated, I would say. So I'm going to drink this, but my caffeine is about to go through the roof. So if later I'm talking very, very fast at the end of the podcast, you'll know why. You've got a small amount there. It's not a lot. But yes, that's a decent whack of caffeine. Chlorogenic acids, this will only be useful as we look at other things in comparison, I suspect. 166 milligrams per deciliter of chlorogenic acids here. So a decent dose, I would say, of chlorogenic acids, which is good news. Because that's good for Lorsinobacter. He's going to be happy down there.

46:34It's going to be happy. So you're actually measuring all these polyphenols. And so this is what's going to be feeding these bacteria in the paper you were talking about earlier. But the fiber content of this would be relatively low compared to something like a darker roast. I think there is more breakdown of certain compounds in darker roasts that make them soluble and easier to extract. Take us to the next coffee. Well, I brought some decaf next, which I thought would be interesting, because I'm curious to see how it stacks up. If you skip the caffeine, what are the polyphenol benefits like in a decaf?

47:06So this is coffee from Brazil. It's a decaf coffee. So you decaffeinate coffee before you roast it. So you take the raw coffee seeds and you decaffeinate those. There's a bunch of ways to do it that have various nice sounding names. All of them are safe. And I think a lot of people hear certain chemical names and inevitably freak out at the idea of ethyl acetate, which is often known as the sugarcane process because no one likes the name ethyl acetate. So, yeah, I think decaf historically has been underrated. I think people don't think of decaf as delicious. I think people see decaf as a compromise, which is a terrible shame.

47:38It's harder to roast as a coffee roasting company. it's harder to make it taste good, but it's actually very possible to make good tasting decaf. I think for a long time, decaf drinkers have been undervalued. They are the true coffee lovers because they're not even getting the chemical hit out of it. They're just drinking it for the taste. And yet they are not well looked after. By the time I made you a flat white, most people would have no idea if it was a good, well-produced decaf, well-roasted, well-brewed. Delicious. Absolutely delicious. I drink a lot of decaf now because I'm quite caffeine sensitive and I value my sleep quite highly.

48:11And so my afternoons are full of decaf. So this would be a way basically to reduce a lot of, I guess, the main health risk about the coffee, right? Which is that it impacts your sleep and we know how important sleep is. Right, I'm precious about that. And you still get, you said, Tim, most of the health benefits? Yes, that's correct. You still get the heart benefits from decaf. And you're making it exactly the same way and it looked to me exactly the same as the ground. It doesn't need special treatment. I'll get my dose in there. Right, and I'll give you a little mix and a share. Excellent. And before we get to the answer, I'm going to ask Tim.

48:45So what is your guess in terms of looking at this on the fiber content and the polyphenols? How do you think it's going to compare with the first one? Well, fiber should be higher. And we know that decaf coffee has the same fiber as regular. As a general rule, if things are more bitter and more tannic and more astringent on your tongue and less smooth, they're more likely to be higher in polyphenol count. It smells stronger to me, like less sort of soft than the last one. There's a lot of reasons for that. It's a different roast level. It's a different country of origin.

49:30I would still say low bitterness. quite gentle friendly in that perspective the polyphenols came in at about 158 milligrams per deciliter so i would say not a statistically significant variation the previous one was about 170 i think so high plenty of those things available there i think the interesting thing for me about instant as a contrast coming into this is that um instant cheats in an interesting kind of way. The manufacturer of instant is motivated by price more than anything else. And so what they need to do to keep this as cheap as possible is to yield as much as is humanly possible from the coffee beans that they start with.

50:12And so through a variety of processes that are only used by instant coffee manufacturers, they can get their extractions up past 30%. They can get it all the way up to about 55%, which means that they can get almost twice as much out of a coffee bean compared to normal people brewing at home. They do that by breaking down some of the insoluble stuff. They sort of hydrolyze it, and then it effectively acts as a bulking agent. And so you would therefore see higher, technically, higher fiber contents in instant coffee than you would see in filter coffee. But there's a trade-off. That's come from less coffee beans in the first place.

50:49And so what I'll do is I'll brew this at a sort of matching strength to these here. And that'll give you a sort of matching strength. And then we can have a little look at the caffeine as well as the polyphenols. Interestingly, they recommend you brew instant quite weak. They recommend a 1 % strength. I'll say one gram per 100 mils, which is surprisingly weak, especially as it's a That's why when I try a strong one, it's virtually undrinkable, isn't it? It's designed to be weak. To be produced quite weak. Now, just as you're making the instant, there'll be people listening to this who have no idea what instant coffee is.

51:26Could you just explain for a minute? It's sitting in a packet. It's lots of these little granules. So instant coffee, the way you make it is basically you make a very large, very strong cup of coffee. And then you freeze dry, ideally, all of the moisture out of it. And what you end up with is a sort of solid, clumped, powdered thing. and what they then do is turn it into a shape that mimics ground coffee to most people to sort of remind you of ground coffee but you could sell this as a pure powder you could sell it as large chunky flakes so really it's like dried coffee and then you rehydrate yeah it's uh it's like a stock powder you know what i mean and you were going to reconstitute it into water and when i was growing up this was the primary way that people drank coffee in the uk but i know that in the States where I also grew up, this was never really the primary way that people had coffee.

52:17And they used to have sort of like a filter coffee in the house. Was the benefit of this really convenience? Is that where this comes from? That's primarily it. You need a kettle and you can just scale it very easily. You need to make 10 mugs of it, one mug of it. It's just 10 spoonfuls or one spoonful. It's very easy, but with all convenience comes compromise. And so as we suppress the price of this, the qualities of raw materials inside instant coffee will inevitably much lower. And then that doesn't start you in a good place. And then it's manufactured to kind of maximum yield, not about maximum flavor.

52:58They do some clever stuff in that when you buy a jar, they will have injected just under the gold foil lid on the top, some aromas. They do an oil extraction, and then they capture some of the aromas of fresh coffee and inject them under the foil lid so that when you pocket open there's a release of aroma that reminds you of fresh coffee even though those flavors were never present in the soluble material underneath this is like selling a house and you're told you should bake bread um and people like oh i'll buy that house it always smells of baked bread but they don't realize it doesn't come with the house this is the uh the coffee equivalent is it pretty much give it a quick stir and we've made coffee which is obviously much faster than me messing around um with a coffee brewer, but let's have a look at what we get as a result.

53:46So this is technically the same strength as the last thing I gave you. Okay, well, it is really dark compared to the previous ones when my hand was underneath it. It was just like a little brown. This is so dark, I can't see my hand at all. So it's a completely different color, and yet you're saying it's the same. It's still 1 % of this water is made of coffee. But 1.3. It doesn't smell anything like the other to at all. It doesn't smell very much of anything, actually. No, because the process of brewing and freeze drying, you lose a lot inevitably in that process, especially the aromatic stuff.

54:22This has used half the amount of coffee to make it, essentially. So it's half the amount of coffee and they've just extracted more, like squeezing an olive, crushing a whole olive. Absolutely. And yield, 38.8 milligrams of caffeine, so about half the caffeine of the first thing you tasted. Okay. It's got half the caffeine. Half the caffeine. 33.55 milligrams per deciliter of chlorogenic acid. So only 20 % of the polyphenols that we had in the... But lots of fiber. In the previous year, but lots of fiber. So interestingly... So that's a strange one. So, you know, if you're just chasing fiber in coffee, this actually is pretty good.

55:01Whether those are the right kind of fibers that are preferred by your gut microbiome, I couldn't say. but it's definitely lower in things like polyphenols. What are your thoughts, Tim? I haven't had actually instant coffee for a long, long time. But actually, it's not that bad. If you get the concentration right, it's perfectly drinkable. It's just not complex. It doesn't have any of the other interesting aromas or flavors. This is what I think of as coffee tasting-like. is the sort of thing you might have served at the end of some dinner. And this is... Yeah, premium end of instant, I would say.

55:42Yeah. It gets much worse. This is as good as it gets. But I would say, if you're chasing the health benefits of coffee, it seems to me that good quality coffee brewed fresh is the best of all worlds because you get lots of what you want and it tastes really good. And for me, that encourages both delight and more consumption. It's easier to drink a good quantity of this stuff if you really enjoy it. So I think that was fascinating. And we have one left to go, don't we? Which is not really a coffee at all. Yeah, we were exploring other ways of having coffee if you don't like it, the taste in the original sort of beverage form.

56:21And so, as people know, I like fermented foods and drinks. And you can have coffee kombucha. and there's two ways of doing this. So kombucha is basically a fermented tea where you use a scoby, which is this blob-like composite of fungi and microbes together in a look like a bit of a jellyfish floating around and they basically like eating tea and sugar. and once you've got a nice big healthy one you can put it in a mixture of tea and coffee and it will produce it will transform that coffee into something new and original that's got a tiny bit of alcohol in it you can't generally taste it's one percent bit of co2 and all these extra chemicals that make it healthy for you and it's a probiotic coffee could be the ultimate it doesn't grow as well.

57:27It prefers tea to coffee, so you don't get as much, and they're harder to grow, so they're harder to find, and you have to then put it back into tea after it's done a bit of its coffee stint. You can't keep it going in coffee. Right. And then there's another way of doing it, which is what I do, is make it in tea the normal way, and then for a second fermentation, you pour it off, and you add a little bit of coffee flavoring with a little bit of extra sugar, and that gives you all the coffee aromas. And you've got a coffee beverage there that's got the combination of both the tea and the coffee and is really, really different, but I find it delicious.

58:08And James, have you had this before? I haven't had this. I've had various coffee kombuchas over the years. And so are you appalled by this idea or exciting? Can we pour a bit and maybe try it? Yeah, I can't actually measure it yet because I need something that's not fizzy because the gas messes with the pipette measurement. So we'll come back to it in a little bit. The challenge typically with coffee and kombucha is that a good cup of coffee has quite a complex acid profile. A bunch of different acids in there contributing to that. And sort of synergies between different acids can get quite complex.

58:39And so once you throw in acetic acid, that vinegar, you can really produce a very strange outcome. You know, it's mixing different vinegars. It doesn't always work out. And so I've mostly tasted pure coffee kombuchas with a sweetened brewed coffee, you know, and the SCOBY's gone to work just on that. And the acid outcome has been challenging. I'm very curious about this one, though. All right, let's try it. Cheers. Cheers.

59:11Well, that's pretty weird. What do you think? Well, I've had these ones before. So the first time you drink it, you're not expecting it. So it's a sort of coffee pop, isn't it? Yeah, it's like a weird combination between like a fizzy sort of, I almost had like apple juice in my mind and coffee at the same time, which is a very strange combination. So they've done this, this is the second fermentation one. So it's basically a kombucha that then done a second ferment. For me, I like my ferments to go a little longer. I feel like this is quite a gentle. It's a bit light. It's a beginner's. I want more acid.

59:46I want more pain. But I think it's a beginner's one. And for someone who doesn't like coffee, could you drink that? Yeah, I could. It's actually, I mean, it's quite interesting. It was weird the first time, but could I drink a glass of that? Definitely. Well, while we're waiting to measure it, because you said it's too fizzy to get the polyphenol answers, I had a couple of final questions I'd love to do. First is, you've given us all of these different types of coffees. I think lots of people were listening to this and saying, imagine that I'm going into a coffee shop rather than making this at home.

1:00:16What is James's top tip for picking the best coffee in that situation? First and foremost, I'm going to be pro-independent coffee shops. They have a different motivation. They're trying to win you over with the quality of the product, not with convenience and familiarity, which is how chains tend to work. So it's worth the gamble to find a good independent coffee shop. They'll care more about the coffee. It'll be fresher. It'll probably be of higher quality. It'll probably be theoretically higher in things like polyphenols, which it's a broad statement and I'm very nervous making it, but you would hope that would be the case.

1:00:48And so that would be the first thing. And then I think, you know, as long as coffee is well brewed, which again, independents these days tend to do well, whether it is a flat white or it is a filter coffee or it is a straight espresso, it's actually a matching kind of extraction of the raw material across all of those things. And so you should see the benefits kind of regardless of your preferred drink. But, you know, people or independent businesses are excited to talk to you about what you like and help you find something that you like. And it's always worth a conversation and finding your local sort of place.

1:01:21I think we don't have that feeling as much anymore of like your local coffee shop. And that's a shame, you know, the thing independents offer over chains too is community, space, experience. So yeah, all those things is why I'm pro-independent business. And one question that we're asked a lot from our listeners was what about people with high blood pressure? So Tim, you've been talking about all the great health benefits of coffee, but you also mentioned, I think, that historically people were told not to drink coffee because it raised blood pressure. If you have high blood pressure, what's your advice?

1:01:54I think if your blood pressure is not under good control, then you have to be very careful with coffee and caffeine. But all the studies suggest that And if you're just starting to drink coffee, it's only the first few weeks that your blood pressure will go up, and then it stabilizes. So I wouldn't advise anyone to completely change their diet or anything they're doing if they don't have stable blood pressure. Get it stable, and then start to slowly introduce coffee into your diet. it's not as far as i'm aware a contraindication if your blood pressure is well controlled i monitor my blood pressure and uh coffee has no effect on that and there's some evidence that long term it might actually reduce your blood pressure got it so you're saying if someone's listening to this and they have high blood pressure but it's under high control and they like coffee you're not saying it's not don't worry about it give up and no though there were old studies they're out of date they showed that people who hadn't been exposed to coffee if you give them large doses short term your blood pressure can go up so obviously if it you know you have a problem short term you don't want to have that problem but if it's well controlled then no real problem long term and long term we know from all the epidemiology that for the average person they will get derived benefit in terms of their heart health.

1:03:26But, you know, the caveat, as always, is everyone is an individual, and all our responses are going to be different. We can't give advice that is going to apply to absolutely everybody. We're talking, at this point, averages. And there's always decaf. Yes. So there's always decaf. And I think the blood pressure story was mainly about the caffeine side of it. So as we've heard, decaffeinated coffee is safe. The chemical processes are now considered very sophisticated and safe. There's plenty on the market. Find one that you like. No need to have caffeine. I think everyone's got to work out, you know, there are lots of factors that affect your caffeine metabolism.

1:04:10Work out what suits you. Experiment. Find out, you know, but for many people, it does get them going in the day and gives them a clarity of thought, in their thought processes and other things that are important. And that's why I have coffee in the morning, but I don't have it at night. All right, let's see what we've got. All right, what have we got? Let me just get you going.

1:04:38Okay, interesting. So caffeine first. This came out at about 33 milligrams, so actually comparable to slightly less than the instant, but comparable to actually a normal strength instant. Chlorogenic acids came out at 55.87. So, you know, 55 to 60 probably realistically, which is, I thought, decent actually, like better than instant and certainly more enjoyable and fun to drink. So, yeah, interesting. Okay, so more polyphenols than instant coffee. There's still a lot less than the coffee, which shows how high the coffee levels were. But there may be, I assume, some polyphenols from the tea in there as well, which may not be picked up by this if they're not specifically chlorogenic acid.

1:05:18So probably a broader profile. Suggesting it's a healthy drink as well. Yeah. I would like to do a quick summary. And today has been really fun because we got to do a science experiment while we were doing this. I think, you know, the key takeaway is that coffee has been really reassessed from something that we were being told was really unhealthy to something that we now understand is actually healthy. And that how we understand that is very much about the way it has the impact on our microbiome and how our microbiome then affects us. And so there are two different components in the coffee that are really important.

1:05:53One is the fiber and one is the polyphenols. And interestingly, there's lots of fiber that is soluble, which is not how I have ever really thought about fiber. And so we heard James making the coffee and you could see like hot water going in, sort of sucking all of this fiber and polyphenols out of this ground up been from a plant. And that, interestingly, there's this great new paper, which we will share as soon as it's peer reviewed and published, which shows that this is then feeding one particular bug that we've now discovered, which I think Lorsonobacter, did I just about manage to pronounce that, Tim?

1:06:35Which we can see basically is like a test for whether or not you drink coffee. So I will get my microbiome retested tomorrow and we'll see whether I think it takes a bit longer than that probably, right, Tim? Which then creates these chemicals as a result of eating this coffee, which we understand. I think you mentioned this thing, quinic acid is just one example of something that we know then has these positive impacts in our body because it sort of passes through into our blood. So that's very exciting. This does not mean you have to drink coffee. There are other ways that you can get fiber and polyphenols, but it means that if you do like coffee, you should be feeling good about this.

1:07:09And that interestingly for a lot of people in the US or the UK, the amount of fiber from your coffee, if you're drinking three or four cups, you say could be very significant because our total fiber intake is so low. And then we did this wonderful test where we tried a variety of coffees. And one of the things that was really striking to me is that the decaffeinated coffee scored just as highly on this polyphenols count as the caffeinated coffee, which is not at all how I would think about it. I sort of put it in my mind as a bit like instant coffee, not really very good for you. Instant coffee, on the other hand, was much lower on the polyphenols.

1:07:49You've really lost a lot. And then we tried this fun coffee kombucha, which is definitely not something I suspect most of our listeners are regularly taking. And interesting, there were really polyphenols in there. And so I think that's really fun to see some real, like that scientific measurement right now that there are some of these good things in that drink. and so the net result I think is don't drink the instant coffee do go to an independent coffee shop and after that it's a lot about your your taste choices and and don't at all feel scared about taking the the decaf because in a way you avoid the the caffeine and you're still getting most of these health benefits it's very good and I look forward there will presumably be more papers to come as we understand more about caffeine and as the number of participants in Zoe grows.

1:08:39Yeah, we'll be able to do one on tea hopefully soon. I would. I'm all up for that one. Wonderful. Thank you so much, James. Thanks for having me back. And thank you, Tim. Thank you. Thank you for joining me on Zoe Science and Nutrition today. It's been really fun to learn about the different types of coffee, their beneficial compounds, and Tim's new research on coffee and the gut microbiome. It's even tempting me to drink coffee myself a little bit. Now, if you're interested in finding out more about your own gut microbiome, something that I do regularly, then you can learn more about becoming a Zoe member, getting your gut microbiome tested and receiving personalized advice on how to eat the best foods to support a healthy gut.

1:09:19You can also get 10 % off your membership. Simply go to zoe.com slash podcast. As always, I'm your host, Jonathan Wolfe. Zoe Science and Nutrition is produced by Yellow Hewins Martin, Richard Willen, and Tilly Fulford. See you next time.

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1:10:24It's designed to be enjoyed, because when a habit brings you joy, you're far more likely to stick with it. So next time you feel like your plate is missing extra plants, do yourself a favor. Try Daily 30. It's a delicious and healthy habit that you'll feel good about, and one that your gut will definitely thank you for. By the way, whenever we talk about Daily 30 as a good source of fiber, we're required to say that it contains four grams of total fat per serving. Obviously, that's all amazing healthy fats from plants. So order yours today at zoe.com slash daily30. See you next time.