18 ms·

A scientific run-down of coffee blooming

84 points by green-eclipse 2y ago

0xbadcafebee 2y ago
In my own attempt to bloom coffee in an Aeropress, the result is, strangely, that it takes much longer to extract the coffee to 'full strength' if I bloom it, compared to not blooming it. If I bloom the coffee, then fill up with water and stir, the result is under-extracted unless I brew for longer. If I just fill up the water immediately and then stir, it takes much less long to brew to the same 'strength'. This is the opposite of what should be happening. But I am using light-to-medium roasted coffee, and this article notes that bloom and roast are interconnected, so perhaps this is normal? All I know is, coffee brewing seems to be much more an art than a science, regardless of how much you try to focus on the science. Dial it in to what tastes good to you, and that's all that matters.
- aidenn0 2y ago
  Blooming in an Aeropress would seem to be unneeded to me if you are agitating.
  - fellowniusmonk 2y ago
    Any type of immersion brew benefits from immediate agitation in my experience, aeropress and french press (which gets aggressively swirled under my hot water tank while it's filling.) You can aggressively stir aeropress as well, you just need to manage it dripping from the bottom using more filters, finer grind, invert method, etc.
    - mikestew 2y ago
      Aeropress should make this acessory standard-issue with their coffee makers, so that we don’t have to rely on other methods to reduce drip-through: https://aeropress.com/products/aeropress-flow-control-filter-cap https://aeropress.com/products/aeropress-flow-control-filter...
      - jcdavis 2y ago
        The inverted method is an even easier way to achieve this :)
        mikestew 2y ago
        You still have to screw a lid on it, how is it any easier than simply screwing on a different lid? Or perhaps you meant “cheaper” instead of “easier”. :-)
- nanomonkey 2y ago
  Perhaps you're letting your water cool? If the water in the kettle cools, and the water in the grounds cools while you let it bloom, then when you combine them they'll have a lower strike temperature then if you were to introduce the water all at once.
- pavon 2y ago
  Could this be a result of low-strength brew draining through during the bloom, which then has to be compensated for with a stronger brew for the rest of the cup? Or is the bloom being done upside down?
- carabiner 2y ago
  I mean 90% of coffee brewing is meaningless rituals. Could you taste the difference between a burr grinder and a blade grinder in the resulting brew? Nope, but endless pages of debate exist on this, grain size distribution, quality of burrs. It has a strong resemblance to the audiophile community.
  - zer00eyz 2y ago
    >> burr grinder and a blade grinder Come on over and we can do just this in my half assed home espresso machine. There will be a difference. The process, roast and general quality of coffee matter. Can one make magical claims about all of this. They sure do and charge an arm and a leg for it. But you can get a quality product an a consistent cup at a reasonable price if you shop around.
  - rangerelf 2y ago
    Of course you can detect the difference between a blade and a burr grinder: how much sludge is at the bottom of your cup? That said, is it really meaningless if it gives you personal satisfaction and peace? Is it any different than any other routine or ritual, like going to church on Sunday?
  - treflop 2y ago
    On blind color difference tests, I score 100% when your average person scores less than 60%. I laugh when people say two colors are the same.
  - romafirst3 2y ago
    Huge difference between burr and blade.
  - 2muchcoffeeman 2y ago
    I mean this is pretty easy to test without making unsubstantiated claims. I’ve done this. We have a range of grinders from $700 to $5000 and did an informal blind tasting. No one had tasted coffee from all grinders. Guesses were revealed simultaneously. 100 percent hit rate.
- charlie0 2y ago
  Are you using the same amount of water in both cases? I sometimes overdilute the coffee because letting it bloom lets the current water drain away.
vundercind 2y ago
I’ve long assumed that the main effect of the bloom is to soak the grounds so the rest of the water you pour in goes through slower, and all the other alleged effects were minor compared to that. But maybe the CO2 removal stuff really is a big deal.
- aidenn0 2y ago
  TFA seems to agree with you; it says that bubbles are an indication that the coffee was unevenly wetted.
  - e40 2y ago
    I’ve taken to stirring my coffee as I pour the hot water in. Definitely seems to ensure that all the coffee grounds ate wetted.
- kitotik 2y ago
  > But maybe the CO2 removal stuff really is a big deal. It’s definitely a thing. There are some super light roasts that if you try to brew them without enough resting time, you can sort of cheat by just grinding the coffee about 30mins before you brew for a hacky quick degas. It really helps get rid of that grassy vegetal taste.
  - romafirst3 2y ago
    There should be no grassy taste, that’s a roast defect and comes from inconsistent roasting. You should find a better roaster. You can roast really light and not get that taste, but you need to be consistent.
    - kitotik 2y ago
      Maybe grassy wasn’t the right term. I don’t mean under developed, it’s kinda bitter and sharp without any sweetness. I’ve experienced this with pretty legit roasters like apollons gold. It seems like the lighter the roast, the more time it needs to degas before it hits the sweet spot.
elwell 2y ago
> 30 grams of coffee, 500 grams water at 205°F Woah, that's too hot IMO, and a bit watered-down. Me: 33g coffee, 350g water at 190°F
- kitotik 2y ago
  16:1 water:coffee ratio is a pretty common starting point. Your brew is pretty intense! I’ve found that darker roasts are much nicer around 195F, I mainly brew very light roast and almost all of them come out under extracted at temps below 200F
  - elwell 2y ago
    Ok, I've been doing 190F for a while so I need to given high temp a try again, thanks for helping me continue exploration
    - kitotik 2y ago
      Good luck! Remember that the only real acceptance criteria in coffee brewing is “do I like it?” =)
- code_biologist 2y ago
  Obviously immersion brewing is different than percolation, but the 16g water : 1g coffee ratio is exactly what James Hoffman recommends in his "Ultimate French Press Technique": https://www.youtube.com/watch?v=st571DYYTR8 https://www.youtube.com/watch?v=st571DYYTR8 For OP's light medium roast (dark roast prefers cooler temps) Hoffman says high temps aren't a problem and shows hard boiling water lead to peak brewing temperatures of 90-93C: https://www.youtube.com/watch?v=K_r5kpXPRYo https://www.youtube.com/watch?v=K_r5kpXPRYo Other youtubers have done blind taste tests and found they liked boiling water brews best with light roast coffee. Not saying your taste is wrong either, just that OP is doing things a way described as ideal by at least one coffee expert! Lots of ways to brew.
- m3kw9 2y ago
  For dark roast yes, but for lighter roasts they are usually more dense and you could get a sour bree
decafninja 2y ago
I went through my coffee hipster phase. But I eventually came to the conclusion that my palate is just too unsophisticated to tell the difference between supposed “hints of blueberry and molasses” in third wave hipster coffee from a boutique roaster versus the cheap coffee that my local newsstand brews every morning. Now my only concession to coffee is brewing a cup on a Technivorm. Also Hawaiian coffee is super smooth and mellow which I like, but serious coffee aficionados apparently don’t like it for the same reason.
- slothtrop 2y ago
  I'm still in that phase, but I like my coffee to taste like coffee. Not necessarily one-note, but not akin to fruity tea (as can be the case brewed with blonde roast, coarse grind, lower water temp, fast percolation). I stick with medium to full-city/espresso roast. Though some single-origin differences can cut through, they don't make much of a difference to me. Where I am enjoying variety more is in my brewing process, french press vs hario switch vs moka pot.
- slumberlust 2y ago
  Everyone's coffee journey is unique and that is awesome! The palate is a bit like a muscle. Some people have bigger/better ones naturally, but everyone can improve what they have with training. There's also value in having a mediocre cup of coffee on the regular. A little saline solution goes a long way in improving palatability.
- soneca 2y ago
  I learned enough to know what I like, what I don’t like, and what doesn’t matter to me. I don’t like expensive coffee that use “fruit” descriptions to their flavors. I like the expensive ones that use “chocolate” or “nuts” descriptions. I like anything from 1:12 to 1:16 ratio (in my routine, 9g to 12g of coffee to 150ml of water). Grain should be fine, but I don’t need a precision grinder. Precise water temperature doesn’t matter much. I like pour over. Not so much french press, aeropress, espresso, or moka pot. I still drink it, just prefer pour over.
- strogonoff 2y ago
  Regular filter coffee at a café, cheapest store-bought Segafredo powder in a moka pot—I still like that more than almost any expensive coffee (as far as black coffee goes, at least), but there is perhaps one particular hand drip the taste of which beats everything. It’s hard to come by and I do not know how to describe it except that it is not sour at all and is diametrically opposite to what many coffee hipsters want (“what is your sourest bean?” is something I overheard once or twice). I got the beans, same beans roasted and ground in the same way in the same shop where I found my desired taste recently, and after making it a couple of times learned that too many things affect the taste. The first time it was good, the second time it was too sour. It is “fun” trying to diff the culprit: water temperature? way of pouring water? psychosomatic factors? A fun fact I re-learned recently and was able to replicate for myself for coffee: there are different sensors in different parts of your tongue that taste different aspects; sides taste sour more so even the shape of your cup affects the result (wider cup may taste more sour with the same coffee).
CoastalCoder 2y ago
One coffee phenomenon I'm curious about: why does old coffee get cloudy? On the day I brew it, it's a dark brown translucent. But if I leave it in the pot overnight, it's definitely more opaque. My wife claims it tastes the same as the day before.
- tptacek 2y ago
  I assume it's just the emulsion breaking.
- ailurooo 2y ago
  fresh coffee has a distinct taste. Maybe your wife is just used to day old coffee lol
  - CoastalCoder 2y ago
    > fresh coffee has a distinct taste. Maybe your wife is just used to day old coffee lol I can definitely taste the difference, and I much prefer fresh coffee. She just can't taste the difference for some reason. Which surprises me, because AFAIK her sense of taste is otherwise normal. One difference might be that I strongly notice "bitter" and find it unpleasant. Maybe bitterness is one of the key differences in stale coffee?
brrrrrm 2y ago
It mentions immersion methods and then never revisits it :( I used to use a Chemex but found the whole process so fickle and involved. I've since switched to a Clever dripper (similar to the hario switch) and found that my coffee life has improved substantially. The basic idea is to let the coffee sit with the water for a bit and then flip a switch to drain it into your coffee. I prefer the consistency of the method and haven't noticed a difference in flavor. My latest project has been attempting to speed up the cold brew process (to get low acidity cold coffee for the summer) and I've taken to using a sous-vide. The idea is that low heat will reduce the time needed for extraction without actually causing the water to leech acidity from the beans. It's worked, but results were kinda meh. I just bought some PH strips to run a more thorough experiment, though.
- pivo 2y ago
  I really enjoy the Clever dripper too. My big revelation (from a James Hoffman youtube video) was that putting the water in first, made the whole process so much faster and maybe even tastier.
soneca 2y ago
I learned that I like without bloom phase. The CO2 getting in the way of extracting flavor might be a good thing, since (at least that is my understanding) the more acidity flavors are extracted later. I like the coffee with more sweetness and less acidity, so I just skip the bloom phase, pouring all at once, it extracts less of the coffee, only the good (for me) parts. Gentle circular pouring can prevent dry coffee blocks and the creation of channels. I also do a little swirl with the filter to flatten the coffee bed. So it is possible to avoid those issues even without the bloom phase. It works for me, even though I am not a hundred percent sure that I got the science of it right. At least, some coffee specialists support my choice: https://youtu.be/miuPSjazpyw?si=_UPZfh9O0YYZwmri https://youtu.be/miuPSjazpyw?si=_UPZfh9O0YYZwmri
- comte7092 2y ago
  Sounds like your grind might be too fine tbh
  - soneca 2y ago
    Idk. I have a cheap grinder that grinds unevenly, so at least it is not uniformly too fine. The barista in the video does use fine grind for this no bloom method, though, so it makes sense. I like the result of the no bloom with my grinder though, so I am happy with it
    - comte7092 2y ago
      If you’re happy with your coffee then that’s what matters in the end. I’d recommend trying a burr grinder though, or getting your coffee pre ground with one, it makes a significant difference in my experience.
- lfuller 2y ago
  > the more acidity flavors are extracted later The first compounds to be extracted with coffee tend to taste sharply sour, shifting to sweet and then to bitter as the brew progresses - you can actually taste this directly by sampling a bit of the coffee that drips out at the start, middle, and end phases of your brew. I found this guide to be helpful when I was first getting started: https://www.homegrounds.co/wp-content/uploads/2021/10/Coffee-compass-illustration-1.jpg https://www.homegrounds.co/wp-content/uploads/2021/10/Coffee...
charlie0 2y ago
I'm curious to how this applies to the Aeropress because in that system, you actively stir the coffee for several seconds.

84 points by green-eclipse 2y ago

In my own attempt to bloom coffee in an Aeropress, the result is, strangely, that it takes much longer to extract the coffee to 'full strength' if I bloom it, compared to not blooming it. If I bloom the coffee, then fill up with water and stir, the result is under-extracted unless I brew for longer. If I just fill up the water immediately and then stir, it takes much less long to brew to the same 'strength'. This is the opposite of what should be happening. But I am using light-to-medium roasted coffee, and this article notes that bloom and roast are interconnected, so perhaps this is normal? All I know is, coffee brewing seems to be much more an art than a science, regardless of how much you try to focus on the science. Dial it in to what tastes good to you, and that's all that matters.

aidenn0 2y ago
Blooming in an Aeropress would seem to be unneeded to me if you are agitating.
- fellowniusmonk 2y ago
  Any type of immersion brew benefits from immediate agitation in my experience, aeropress and french press (which gets aggressively swirled under my hot water tank while it's filling.) You can aggressively stir aeropress as well, you just need to manage it dripping from the bottom using more filters, finer grind, invert method, etc.
  - mikestew 2y ago
    Aeropress should make this acessory standard-issue with their coffee makers, so that we don’t have to rely on other methods to reduce drip-through: https://aeropress.com/products/aeropress-flow-control-filter-cap https://aeropress.com/products/aeropress-flow-control-filter...
    - jcdavis 2y ago
      The inverted method is an even easier way to achieve this :)
      - mikestew 2y ago
        You still have to screw a lid on it, how is it any easier than simply screwing on a different lid? Or perhaps you meant “cheaper” instead of “easier”. :-)
nanomonkey 2y ago
Perhaps you're letting your water cool? If the water in the kettle cools, and the water in the grounds cools while you let it bloom, then when you combine them they'll have a lower strike temperature then if you were to introduce the water all at once.
pavon 2y ago
Could this be a result of low-strength brew draining through during the bloom, which then has to be compensated for with a stronger brew for the rest of the cup? Or is the bloom being done upside down?
carabiner 2y ago
I mean 90% of coffee brewing is meaningless rituals. Could you taste the difference between a burr grinder and a blade grinder in the resulting brew? Nope, but endless pages of debate exist on this, grain size distribution, quality of burrs. It has a strong resemblance to the audiophile community.
- zer00eyz 2y ago
  >> burr grinder and a blade grinder Come on over and we can do just this in my half assed home espresso machine. There will be a difference. The process, roast and general quality of coffee matter. Can one make magical claims about all of this. They sure do and charge an arm and a leg for it. But you can get a quality product an a consistent cup at a reasonable price if you shop around.
- rangerelf 2y ago
  Of course you can detect the difference between a blade and a burr grinder: how much sludge is at the bottom of your cup? That said, is it really meaningless if it gives you personal satisfaction and peace? Is it any different than any other routine or ritual, like going to church on Sunday?
- treflop 2y ago
  On blind color difference tests, I score 100% when your average person scores less than 60%. I laugh when people say two colors are the same.
- romafirst3 2y ago
  Huge difference between burr and blade.
- 2muchcoffeeman 2y ago
  I mean this is pretty easy to test without making unsubstantiated claims. I’ve done this. We have a range of grinders from $700 to $5000 and did an informal blind tasting. No one had tasted coffee from all grinders. Guesses were revealed simultaneously. 100 percent hit rate.
charlie0 2y ago
Are you using the same amount of water in both cases? I sometimes overdilute the coffee because letting it bloom lets the current water drain away.

vundercind 2y ago

I’ve long assumed that the main effect of the bloom is to soak the grounds so the rest of the water you pour in goes through slower, and all the other alleged effects were minor compared to that. But maybe the CO2 removal stuff really is a big deal.

aidenn0 2y ago
TFA seems to agree with you; it says that bubbles are an indication that the coffee was unevenly wetted.
- e40 2y ago
  I’ve taken to stirring my coffee as I pour the hot water in. Definitely seems to ensure that all the coffee grounds ate wetted.
kitotik 2y ago
> But maybe the CO2 removal stuff really is a big deal. It’s definitely a thing. There are some super light roasts that if you try to brew them without enough resting time, you can sort of cheat by just grinding the coffee about 30mins before you brew for a hacky quick degas. It really helps get rid of that grassy vegetal taste.
- romafirst3 2y ago
  There should be no grassy taste, that’s a roast defect and comes from inconsistent roasting. You should find a better roaster. You can roast really light and not get that taste, but you need to be consistent.
  - kitotik 2y ago
    Maybe grassy wasn’t the right term. I don’t mean under developed, it’s kinda bitter and sharp without any sweetness. I’ve experienced this with pretty legit roasters like apollons gold. It seems like the lighter the roast, the more time it needs to degas before it hits the sweet spot.

elwell 2y ago

> 30 grams of coffee, 500 grams water at 205°F Woah, that's too hot IMO, and a bit watered-down. Me: 33g coffee, 350g water at 190°F

kitotik 2y ago
16:1 water:coffee ratio is a pretty common starting point. Your brew is pretty intense! I’ve found that darker roasts are much nicer around 195F, I mainly brew very light roast and almost all of them come out under extracted at temps below 200F
- elwell 2y ago
  Ok, I've been doing 190F for a while so I need to given high temp a try again, thanks for helping me continue exploration
  - kitotik 2y ago
    Good luck! Remember that the only real acceptance criteria in coffee brewing is “do I like it?” =)
code_biologist 2y ago
Obviously immersion brewing is different than percolation, but the 16g water : 1g coffee ratio is exactly what James Hoffman recommends in his "Ultimate French Press Technique": https://www.youtube.com/watch?v=st571DYYTR8 https://www.youtube.com/watch?v=st571DYYTR8 For OP's light medium roast (dark roast prefers cooler temps) Hoffman says high temps aren't a problem and shows hard boiling water lead to peak brewing temperatures of 90-93C: https://www.youtube.com/watch?v=K_r5kpXPRYo https://www.youtube.com/watch?v=K_r5kpXPRYo Other youtubers have done blind taste tests and found they liked boiling water brews best with light roast coffee. Not saying your taste is wrong either, just that OP is doing things a way described as ideal by at least one coffee expert! Lots of ways to brew.
m3kw9 2y ago
For dark roast yes, but for lighter roasts they are usually more dense and you could get a sour bree

decafninja 2y ago

I went through my coffee hipster phase. But I eventually came to the conclusion that my palate is just too unsophisticated to tell the difference between supposed “hints of blueberry and molasses” in third wave hipster coffee from a boutique roaster versus the cheap coffee that my local newsstand brews every morning. Now my only concession to coffee is brewing a cup on a Technivorm. Also Hawaiian coffee is super smooth and mellow which I like, but serious coffee aficionados apparently don’t like it for the same reason.

slothtrop 2y ago
I'm still in that phase, but I like my coffee to taste like coffee. Not necessarily one-note, but not akin to fruity tea (as can be the case brewed with blonde roast, coarse grind, lower water temp, fast percolation). I stick with medium to full-city/espresso roast. Though some single-origin differences can cut through, they don't make much of a difference to me. Where I am enjoying variety more is in my brewing process, french press vs hario switch vs moka pot.
slumberlust 2y ago
Everyone's coffee journey is unique and that is awesome! The palate is a bit like a muscle. Some people have bigger/better ones naturally, but everyone can improve what they have with training. There's also value in having a mediocre cup of coffee on the regular. A little saline solution goes a long way in improving palatability.
soneca 2y ago
I learned enough to know what I like, what I don’t like, and what doesn’t matter to me. I don’t like expensive coffee that use “fruit” descriptions to their flavors. I like the expensive ones that use “chocolate” or “nuts” descriptions. I like anything from 1:12 to 1:16 ratio (in my routine, 9g to 12g of coffee to 150ml of water). Grain should be fine, but I don’t need a precision grinder. Precise water temperature doesn’t matter much. I like pour over. Not so much french press, aeropress, espresso, or moka pot. I still drink it, just prefer pour over.
strogonoff 2y ago
Regular filter coffee at a café, cheapest store-bought Segafredo powder in a moka pot—I still like that more than almost any expensive coffee (as far as black coffee goes, at least), but there is perhaps one particular hand drip the taste of which beats everything. It’s hard to come by and I do not know how to describe it except that it is not sour at all and is diametrically opposite to what many coffee hipsters want (“what is your sourest bean?” is something I overheard once or twice). I got the beans, same beans roasted and ground in the same way in the same shop where I found my desired taste recently, and after making it a couple of times learned that too many things affect the taste. The first time it was good, the second time it was too sour. It is “fun” trying to diff the culprit: water temperature? way of pouring water? psychosomatic factors? A fun fact I re-learned recently and was able to replicate for myself for coffee: there are different sensors in different parts of your tongue that taste different aspects; sides taste sour more so even the shape of your cup affects the result (wider cup may taste more sour with the same coffee).

CoastalCoder 2y ago

One coffee phenomenon I'm curious about: why does old coffee get cloudy? On the day I brew it, it's a dark brown translucent. But if I leave it in the pot overnight, it's definitely more opaque. My wife claims it tastes the same as the day before.

tptacek 2y ago
I assume it's just the emulsion breaking.
ailurooo 2y ago
fresh coffee has a distinct taste. Maybe your wife is just used to day old coffee lol
- CoastalCoder 2y ago
  > fresh coffee has a distinct taste. Maybe your wife is just used to day old coffee lol I can definitely taste the difference, and I much prefer fresh coffee. She just can't taste the difference for some reason. Which surprises me, because AFAIK her sense of taste is otherwise normal. One difference might be that I strongly notice "bitter" and find it unpleasant. Maybe bitterness is one of the key differences in stale coffee?

brrrrrm 2y ago

It mentions immersion methods and then never revisits it :( I used to use a Chemex but found the whole process so fickle and involved. I've since switched to a Clever dripper (similar to the hario switch) and found that my coffee life has improved substantially. The basic idea is to let the coffee sit with the water for a bit and then flip a switch to drain it into your coffee. I prefer the consistency of the method and haven't noticed a difference in flavor. My latest project has been attempting to speed up the cold brew process (to get low acidity cold coffee for the summer) and I've taken to using a sous-vide. The idea is that low heat will reduce the time needed for extraction without actually causing the water to leech acidity from the beans. It's worked, but results were kinda meh. I just bought some PH strips to run a more thorough experiment, though.

pivo 2y ago
I really enjoy the Clever dripper too. My big revelation (from a James Hoffman youtube video) was that putting the water in first, made the whole process so much faster and maybe even tastier.

soneca 2y ago

I learned that I like without bloom phase. The CO2 getting in the way of extracting flavor might be a good thing, since (at least that is my understanding) the more acidity flavors are extracted later. I like the coffee with more sweetness and less acidity, so I just skip the bloom phase, pouring all at once, it extracts less of the coffee, only the good (for me) parts. Gentle circular pouring can prevent dry coffee blocks and the creation of channels. I also do a little swirl with the filter to flatten the coffee bed. So it is possible to avoid those issues even without the bloom phase. It works for me, even though I am not a hundred percent sure that I got the science of it right. At least, some coffee specialists support my choice: https://youtu.be/miuPSjazpyw?si=_UPZfh9O0YYZwmri https://youtu.be/miuPSjazpyw?si=_UPZfh9O0YYZwmri

comte7092 2y ago
Sounds like your grind might be too fine tbh
- soneca 2y ago
  Idk. I have a cheap grinder that grinds unevenly, so at least it is not uniformly too fine. The barista in the video does use fine grind for this no bloom method, though, so it makes sense. I like the result of the no bloom with my grinder though, so I am happy with it
  - comte7092 2y ago
    If you’re happy with your coffee then that’s what matters in the end. I’d recommend trying a burr grinder though, or getting your coffee pre ground with one, it makes a significant difference in my experience.
lfuller 2y ago
> the more acidity flavors are extracted later The first compounds to be extracted with coffee tend to taste sharply sour, shifting to sweet and then to bitter as the brew progresses - you can actually taste this directly by sampling a bit of the coffee that drips out at the start, middle, and end phases of your brew. I found this guide to be helpful when I was first getting started: https://www.homegrounds.co/wp-content/uploads/2021/10/Coffee-compass-illustration-1.jpg https://www.homegrounds.co/wp-content/uploads/2021/10/Coffee...

charlie0 2y ago

I'm curious to how this applies to the Aeropress because in that system, you actively stir the coffee for several seconds.