This is Why Your Coffee is Astringent (and How to Stop It)

本站添加: 2026-05-12

[00:00:07]This video is brought to you by Squarespace.

[00:00:12]Oh, that is aringent. Oh, now that is a word coffee people love to use. When referring to a dry or bitter or some sort of unpleasant taste in the mouth, we throw around the word astringent. So, as you can imagine, this whole video is going to be about aringency. What's causing it or what do we think is causing it? What does science say is causing it? And how can we potentially get away from it to not have that dryness in our cups? We understand aringency based off of its presence in other industries like chocolate, wine, and tea. There is way more science that has been applied to these areas than to coffee. And so we have a very rich understanding of how aringency is enacted in those areas. Aringency, just very briefly, is essentially the drying or the mouth puckering or the roughness that is associated with certain compounds that you ingest that go and they essentially block up the lubricating saliva in your mouth. It literally blocks those up, kind of stops them from producing it. So then the surfaces in your mouth as they're rubbing against each other actually feel like they have a bit of a friction. Get an underripe pmen or get a red wine that's heavy in tannins or get something like a really unripe banana. All of these things will give you a physical drying on your tongue that you cannot mistake for anything else.

[00:01:24]I have noticed that there is a huge misunderstanding with enthusiasts and professionals alike on what arringency is. Very often aringency gets conflated with bitterness and that is not right.

[00:01:36]Now are there times where heavily bitter coffees are also astringent? Absolutely.

[00:01:40]In fact that's one of the most common connections I have with aringency is it is also accompanied by bitterness. But that doesn't mean that they are equal or that they are related. In fact, they are very different. Bitterness is a taste sensation whereas aringency is a physical sensation. So people use and abuse the term in coffee to have anything that seems dry even in the slightest that's astringent. Even if it's a bitterness first and foremost, they'll describe it as aringent. So just for a brief example to kind of give you an idea of what I mean by being confused, we say coffee very often. We say is sweet. We're going for a really sweet cup. Sweet implies sugars. There are sugars in coffee. They're more before it's roasted and they're roasted away. But even with the lightest roast possible, you still do not have enough sugar that comes through the final brew to where it's perceptible by the threshold of the human pallet. We cannot taste the sugar in coffee. So what are we interpreting as sweet? Well, we're interpreting different vault organic compounds, esters, whatever. We're interpreting them as sweet. Our brain is tricked into thinking it's sweet. So when we say something is sweet, we're referring to the perception. Same thing with acidity. There was a really interesting study by Morton Munchow that showed that there was more inherent citric acidity in a Brazilian lowquality coffee than a really high quality washed Kenya coffee. But you put it in front of any panel and say which one tastes more citric there. It's with 100% people will choose the Kenya coffee. There's just no question that it will have a more intense citric acidity. But there was a ton more inherent citric acidity in said Brazilian. There are perceptions based off of the different kind of signals going off in our head based off of the different compounds we are ingesting bas based off the different aromatics etc etc etc. And the last example would be bitterness with carbonic acid. Acid by its definition is not bitter. It's acidic. It's sour. But when you give someone who does not enjoy carbonated water a cup of carbonated water, very often they describe it as bitter due to the way it is received on the tongue and it gives you a quick harsh hit. And people often describe that as bitterness. In fact, I still taste bitterness on really fresh coffees due to the carbon dioxide that's still in there. You brew it, you get carbonic acid that can maybe be dissipated with more rest. In the same way, people will call things dry where maybe it's just a really hollow body or maybe it's a really bitter coffee and you think, "Wow, that's really asting." Because you kind of have all these signals going on in your mind that give you the perception of dryness even if your tongue is not physically grating against the roof of your mouth. Now, the coffee I've been brewing is this coffee from say it's a roaster I actually work for.

[00:04:14]Uh, absolutely delicious, but I mean it's in the box, right? It's in this kind of Squarespace, which is a sponsor of today's video. Squarespace is a wonderful online resource that you can use if you are an entrepreneur, a creative, or someone that wants to get your thoughts out into the world. You get online, you can grab your domain through Squarespace, and you can build your own website showcasing your products or whatever it is that you do, whether it's writing, poetry, maybe you're a poet and you didn't know it.

[00:04:38]Maybe you write haikus, 575 syllables, you know, the good stuff. You can put a blog on there. You can do a shop on there. You can do a place for you to upload your photos. You can do a community board on there to communicate with the people who are a fan of what you do.

[00:04:52]Super easy. Click, drag, drop, go. Done.

[00:04:55]Don't need to know how to code. You just need to know what kind of look you're going for. And you can put pictures on there. Word art. Who knows word art?

[00:05:02]This is better than word art. You can use the code down below, Lance Hedrickk or www.squarpace.com/lanceedric.

[00:05:07]And you'll get 10% off your first domain purchase on Squarespace by using that.

[00:05:11]helps me, helps you, helps the channel, helps everybody, and you can put your cool things online for the world to kind of see. But anyway, thank you Squarespace for sponsoring the video.

[00:05:19]Uh, let's continue on. There's an awesome paper that came out in 2025 that I'll be relying on deeply in this video to kind of explain this mechanism, or at least where where the science is now leading, although it's definitely not complete. But we need to go back to the beginning when it was first really understood that coffee did have a stringency in it back in the 70s and 80s. And back then it was also realized that tannins were not the things causing it. So in order for us to have this astringency in these other areas, you have polyphenols ingesting polyphenol rich foods that cause that physical sensation based off of the stopping of the lubrication by saliva. That is not happening in coffee. Now some of you may be rightly pointing out that coffee has polyphenols. You'll also wrongly be saying that all that massive amount of chlorogenic acid in there are all polyphenols. I guess it's more of an argument of what side of the the aisle you're on. Dr. Dr. Samos Smarke chemist down out in Zurich argues that those are not necessarily polyphenols and it's because they don't have enough hydroxal groups similar to those of tannins and the other polyphenols that are referred to causing aringency. I will actually read his words so that we're not misinterpreting Dr. Smurk. But let's clarify first. Coffee does not contain tannins. This is a myth that I've heard in lots of brewers cup competitions, people talking about the tannins in the coffees. I've heard this by at coffee shops that similar to wine, coffee has tannins and it can give you the dryness.

[00:06:35]and we're airrating it to get rid of the tannins, whatever it might be. But coffee doesn't contain tannins. A tannin is a polymeric polyphenol that causes precipitation of proteins, such as, for example, present in wine. Coffee doesn't even contain much polyphenols, not in the sense of the definition of secondary plant metabolites. There are very small amounts of some molecules that could be considered polyphenol. For example, dchlorogenic acid. Tannin molecules by definition contains a large number of hydroxal units. As far as current state of knowledge is a coffee does not contain significant amount of any chemically similar compounds. In order for us to get the astringency we're getting in these other areas like with tea and wine and chocolate, we need to have these polyphenols because that is what all the studies are on is arringency based off of that. But we're experiencing it objectively in our coffee. So where is it coming from? That leads me to an interesting thesis that a friend of the channel, a friend of mine, Dr. Jonathan Gia had some years ago about it being potentially with a specific particle. So if you can increase the efficacy of your filtration, maybe you could filter out some of the astringency. I do still think that is really interesting and I think that it can relate though I don't think in the end that was actual cause of aringency, a specific particle or anything like that. Instead, we look at this new thesis by Dr. Brienne Lynn.

[00:07:56]Now, I've relied on some of her publications in the past, specifically her thesis in order to talk about acidic content coffee I used in a video from a year ago, but there was a follow-up on a stringency in general that came out recently that is incredibly incredibly insightful and I think is in the right direction. Hopefully, more will be done in this area. So, what she did in her thesis out at Ohio State is they did what's called a fractionation process with coffee. They were able to essentially separate coffee into different compound groups. Now they weren't separating it into single compounds but compound groups and they had trained tasters Q- graders etc on the table and they were looking for for this paper the taste of aringency. So they had a reference for all of them that was objectively astringent that was causing that arranging sensation in their mouth in order to calibrate upon as well as a definition of what that might be. And before every tasting session, one to two 20-minute tasting sessions daily over five or so days, they were looking at these different fractionated cups of coffee and were looking for what had the most arringency, going back and forth and back and forth in blind testings. They were able to get down one specific group that was containing the most astringent properties. And this was the fraction 9.6.4 in the paper in the caption. Feel free to go check it out. What they discovered was the carriers of this arringency were melanoid. Now, you may or may not know what a melanoid is, but it's what gives coffee that brown color.

[00:09:18]It's it comes through the malard reaction and is unavoidable. You have to have melanoidins if you're going to have coffee that's drinkable. Even if you roast it as light as possible, you have that malard reaction and you're getting these melanoidins. Now, there is a wide variety of melanoins. I read one piece of literature saying 51% of the roasted coffee, but of course that will depend on the roast, etc., etc. during the roasting process from green to brown. Green does have the most chlorogenic acids and it's the breakdowns the phenolic compounds that come off of it that potentially are being absorbed into the melanoid and the structures that is causing this astringency. It's either a slightly different mechanism or the same mechanism going on just it's not requiring a polyphenol. you have these phenolics that are coming off of the chlorogenic acids during the breakdown of them over the course of the roasting uh phase that are being imparted onto these melanoid structures. Now melanoidans have a vast variety of sizes. What was interesting is in this fraction 9.6.4 they found that it was actually a really small size a subset of these melanoidins. So something that was way smaller than normal.

[00:10:27]People could say light roast is really astringent because it has the most chlorogenic acids and that's a polyphenol obviously. So polyphenol rich light roast most astringent boo light roast or others would say dark roast really bitter bitter is aringent boo dark roast. It would seem that across all you could have these melanoidins that contain these phenolics that could be imparting this aringency. After some had heard some of this at a lecture before the p paper was published. He hypothesized that actually the darker you rose something the more you could actually break down those phenolic compounds in the melanoid and structure and it could actually take away stringency. Yet again, he was saying that with where current studies are that really fast light on the borderline of underdeveloped roast are at the worst area for potential arringency because they're producing enough melanoids, breaking down enough chlorogenic acid, creating enough of those phenolic compounds to be absorbed into the melanoid and structure. And the darker you roast, the more you're able to burn them out, the less potential arringency there is. There is evidence from, I believe, 2011. We'll post a paper here. there is a group that has already been identified as giving arsting properties and this group is something that only comes out with darker roasted coffees. So it's an interesting balance here where we have a previously understood area where some astringency can be traced to. Then we have a new understanding of an area where a lot more of the astringency that we perceive in coffee is traced to. Oh, by the way, if you're enjoying this stuff, if you enjoy, you know, getting the sciency stuff to democratize it, if you enjoy the amounts of things that I do as regards coffee experimentation, trying to help you brew better coffee at home, reviewing things, whatever, please consider hitting the like and the subscribe. Really helps me, helps the channel, and um I would love it. It would just be it would be the best.

[00:12:08]Anyway, let's continue on with talking about a nerdy nerdy nerdy thing like the mechanism of aringency in coffee extraction.

[00:12:16]Okay, Lance, cool. We now understand where hypothetically aringency is happening, how it actually works and what it's actually doing to our tongue.

[00:12:22]How do we avoid it? Even though these melanoidins are definitely the smallest ones that are essentially produced in roasting, they still extract very slowly. They extract quite slowly. And so in order to fully extract them to get out these phenolic compounds that are inside of it that are causing based off of this most recent study by Dr. Brienne Lynn, we have to extract quite a bit.

[00:12:44]The intuition of a lot of people has been correct for some years that the more you extract something, the more aringent it can potentially become. But of course, this is also where definition comes into play. There are people who will have a low extraction and think that it's arringent when in reality that's probably not a stringency. It's probably an imbalance and you're perceiving it as aringent. You're perceiving it as dry or bitter or something along those lines when it's not actually chemically doing that. We can have some different signals coming in from vol organic compounds that are causing us to have perceptions of dryness when it's not actually dry. You can make a small tweak and make that better. Whereas, if you're pushing extraction really far, that's when you're going to introduce a lot more potential arringency, especially with really lightly roasted coffees.

[00:13:28]If you were drinking the light to ultra light style coffees, I would not push extraction very far. And this also aligns with my personal experience. I have dropped to lower extractions in recent years. A because I think higher extraction mutes aroma due to the extraction of more acids, not necessarily good ones, volatile organic compounds, not necessarily good ones.

[00:13:46]Higher concentrations of those and it's dipping the concentrations of ones that we actually want to experience in coffee. But in addition to that, I noticed that the further you pushed coffee, the more aringent it became. And it did seem that when you push light roast, even though there was more to give in light roast, that it was getting it had a low ceiling. and I was getting arringency relatively quickly.

[00:14:07]It is really interesting that years ago Scott Rayo a coffee professional provocator was pushing this idea of you want to extract coffee as high as possible before you hit aringency. So even in that kind of inferred one can infer from that that there was this understanding of the more you push something the more aringent it can become. I just believe that ceiling is a lot lower than we previously understood.

[00:14:29]And so understanding what arringency is and how it's affecting our coffees, it's going to help us dial in better coffees.

[00:14:35]Now, when you get to darker coffees, I do think that arringency obviously can be there, but I do find it to be a lot less prevalent than in really lightly roasted coffees as far as when I'm brewing. So, when I brew a darker roasted coffee, you're also not wanting to push extraction very high because so much has been burnt out of the coffee.

[00:14:51]And there are a lot more negative compounds in dark roasted coffees that can taste really awful. So if you push extraction, you want more of those in your cup. Good for you. But you can get more smoke, more rubber, more leather, more tire, all this awful tasting things if you're really pushing the extraction.

[00:15:06]And it also just becomes less enjoyable as far as the body goes the more you push extraction. And you can creep in some of these astringent notes because even if you roast it quite dark, you can still maintain some of those phenolic compounds in the melanoidins themselves.

[00:15:21]The idea here is don't push extraction super high when you're with a a light or ultra light roast. If you're experiencing aringency, maybe lessen the extraction a bit. If you're doing a really dark roast, maybe you're not having a stringency, but just a bitterness that you're misinterpreting as aringency, maybe lessen the temperature of the water. Again, you are working with this idea of lessen the extraction. So, if we're pushing 23 24% and we just can't get around this arringency, no matter what filter we paper we use, maybe it's time to lower the extraction. If we have a darker roasted coffee and it's not tasting as good as we thought at a certain ratio, maybe lower the ratio and you'll be able to get a little less of that physical drying. In the end, the idea is about improving your coffee and having a better understanding of why it's tasting the way it tastes, even on a chemical level, will allow us to get to where we want to go much more quickly. TLDW, you taste a coffee and you're like, "Wow, that's dry." First, let's break down, is it actually dry? I need you to try that unripe pment, a green banana, a high high tannin red wine, cacao, 100% dark chocolate, something like that, in order to have a nice reference of what physical drying actually is. If so, all right, we have a problem with aringency.

[00:16:33]This is likely coming from that 9.6.4 from the Dr. Brienne Lynn paper. And what that means is we have these melanoidins that have the phenolic compounds in this coffee that are rich enough to affect our cup. That means very immediately lessen your extraction.

[00:16:48]Now, they can be extracted rapidly, which just means you would need to extract your coffee even more rapidly to get rid of those. There's another potential mechanism of something that can cause dryness that have been that's been floated around again by Dr. Gier, and he's chatted with Simo and some comments on Instagram about it, but is this potential of small sub five micron kind of fines that can have a similar experience to dryness on your tongue as these phenolic compounds within the melanoid structures. Uh, and if that's the case, you can try using maybe a thicker paper filter to lessen arringency. There have been a lot of anecdotes online of people doing that.

[00:17:20]Though there is no proof that this is actually an actual aringency inducing situation, though heavy bitterness again can be linked to aringency or the idea of drying, I should say. And so having a thicker filter paper can also help you pull out those microparticles which could be obuscating your palette, making you taste bitter, which could make you perceive that as a stringency. Now, if you're using a dark roasted coffee, maybe we extract less. If you still get it, it could just be a thing with that coffee. There are coffees that are just more inherently astringent than others due to how darkly they may be roasted.

[00:17:52]This coffee actually isn't a stringent.

[00:17:54]I was acting earlier. I hope that was interesting, maybe helpful as we go through, and I love to go through scientific papers every now and then, but I'm really excited about the direction of this specific one by Dr. Brienne Lynn. am excited about whatever follow-ups may be done with other people in the coffee science community in order to further understand this terrible thing of aringency on coffee, which we definitely want to get rid of as best as we can. And again, if you're interested in any of the papers, they're all linked down below. And that's about it for me today. Thank you so much for watching.

[00:18:24]Regardless of how you brew your coffee, I hope that you brew something tasty today. Sans aringency and cheers.