OK, I don't often post twice in one day about the coffee I'm drinking, but apparently today is special.
I just opened a bag of natural 74110 varietal Ethiopian roasted by @timwendelboe, and what a home run ! This is both an amazing green and amazing roast; I brewed it at 1:17 in a V60 with my usual recipe (available on my blog, see link in bio), and obtained the highest extraction yield I ever measured on any V60 brew so far: 1.60% TDS for a 320g beverage, for an average extraction yield of 23.3% !
But this is not just about numbers; it is the first coffee I would qualify as a "flower bomb". It is like the quintessence of Ethiopian floral aromas, backed by a very bright and juicy acidity that reminds me of ripe figs. What a great coffee !
#coffeegeeks #pourover #coffee #coffeeadastra
This morning I decided to finally try @father_coffee’s Jasper natural carbonic macerated SL28 & SL34 Kenyan that I won in their Instagram giveaway. It is a great coffee; it’s really fun to try such a special processing method from Kenya. It is roasted very well, maybe a tad more developed than I’m used to, but still well within my comfort zone.
I get a very sweet and fruity cup, with notes of black cherries, blackberries, cranberries and tropical fruits. The winey taste is not as pronounced as in their Amber which was the same coffee but carbonic macerated and washed, but there’s a distinct taste I’m unable to describe that reminds me a lot of @gardellicoffee’s M’zungu project from 2018, which I really loved.
I made it with my usual V60 recipe, with Rao/Perger water at 1:17, ground at 7.0@700 RPM on the EG-1 grinder (burrs touch at 1.6). I obtained a 324g beverage at 1.53% TDS, for an average extraction yield of 22.6%. I’m starting to think that the @brewcoat is getting me a ~0.03% TDS increase on all my brews because my @mybrewista artisan gooseneck kettle was not stable enough thermally !
Thanks @sasasestic for taking the efforts to help develop this special coffee too !
#coffeeadastra #pourover #coffeegeeks
Today I finally got to try @tunnelespresso and Vassily & Julien served me the best batch brew coffee I ever had, and honestly the first batch brew I ever truly enjoyed !
It was also a bean I know well, Andy’s @canadianroastingsociety Ethiopian Nano Challa, and it was prepared extremely well, I couldn’t notice any roast or brew issue even in diagnostics mode. I wouldn’t be surprised if that was a ~21-22% extraction yield I was drinking. Finally, here’s a coffee shop I’m happy to recommend in Montreal :) Finding the shop is a challenge and you might get lost in Montreal’s underground mazes, but that’s part of the adventure. It will make it even more worth it when you finally find the blue neon glare of Tunnel. Make sure you check the store hours before you go if you’re a night owl like me, they’re mostly open early in the day.
Also thanks to @magalie.steve for installing that beautiful new @waterforcoffee.ca RO system + Mg booster that probably helped a lot !
Pictures are by Andy and @magalie.steve
#coffeegeeks #coffee #montrealcoffee
Is this placebo or the consequence of a material sensory phenomenon ? I have no idea, but the same coffee does appear different in the two @kruveinc glasses 😁
Today I’m testing them out with a very weird and enjoyable coffee ! @father_coffee generously sent me a carbonic macerated + washed Kenyan, their Amber 074, which I brewed as a V60 with my “classical” method an Rao/Perger water (45 sec bloom; see link in bio for all details on my blog). I got a 323g beverage at 1.51% TDS (22g dose) for an average extraction yield of 22.2%. The result is a deep, sweet and intense cup with strong notes of blackberry and a winey finish that I really enjoy. As it cooled, I noticed notes of caramel and blueberry too. For me, the Kruve glass on the left emphasized the juicy and sweet side of it; and the one on the right emphasized a bright acidity and more floral notes. Not exactly a controlled experiment or a blind tasting, but it’s interesting!
One of my worries was that they’d be too big because I got used to drink my V60s in very small espresso glasses, but I must say I enjoy their size, it’s a bit less than a mug. I could split my 324g beverage in both and I had about two espresso glasses of coffee left. I have been excited to try these glasses for several months now since I backed their kickstarter project, so I’m happy that they live up to my expectations 😀
#coffeegeeks #pourover #kruve #coffeeadastra #coffee
Who wants more discussion of bloom duration ? 🤓 Today I tried preparing two V60s with a 3 minutes bloom on different coffee beans, and both tasted much worse and showed only a slight ~0.2% extraction yield (EY) increase over my usual 45 seconds bloom !
The first brew was Andy’s @canadianroastingsociety Nano Challa Ethiopian (roasted this month), it’s a very well developed roast that tastes great w/o any astringency at ~22.5-23.0% EY. The long bloom had 22.8% EY and tasted astringent, muddy and slightly bitter. I think I may have caused some clogging which could maybe explain the worse taste.
The second brew was @ghowellcoffee’s Tabe Burka Ethiopian (roasted in February and vac sealed since then). I usually get ~21% EY with it and absolutely love its floral, lime and chocolate taste. But this time it tasted bitter, ashy and muddy ! For this brew I don’t see what else could have caused the worse taste.
I’ve heard a few similar negative experiences with the long bloom so far (@aryanjoshani ) and some friends have had a mix of great improvement or a more mitigated improvement by using it.
This tells me using a longer bloom probably only works great on *some* coffee beans ! I now suspect the lighter roasts come out better with a longer bloom, which would make it a bit more likely that the long bloom’s benefits has something to do with coffee cellulose being too stiff in lighter roasts.
We need more data, but that would be incredibly useful if we could tweak the bloom when we find a roast is too light for our taste 😮
#coffeeadastra #coffeescience #coffeegeeks #pourover #longassbloom
Today I decided to gather more evidence on how @umeshiso_'s long-ass bloom affects extraction yield (EY). I brewed the same coffee as yesterday, with a 45 sec and then a 3 min blooms. I added short water pulses during the 3 min bloom so that coffee particles absorb all the water they can during the bloom. Again, the long bloom caused an increase in TDS from 1.44% (21.4% EY) to 1.53% (22.3% EY) and a sweeter taste !
The first two images show my brew curves; they put to rest my confusion that yesterday’s long-bloom brew was slower post-bloom. This was caused by my waiting for each pour to completely drawdown 😅 Now both brews have a similar V60 flow rate (~2.5 g/s) and bloom-corrected drawdown times within 4 seconds of each other.
In the next image, you'll find my last brew's best-modeled liquid retained ratio (LRR) increase during brew (see my earlier few posts for more). This time I did not wait for the drawdown between each pour. The LRR increased more slowly (blue line) than the short bloom case (red line), but this time it allowed me to reach a higher LRR of 98% of its final value by the end of the bloom (blue circle), rather than just 60% (red circle). In other words, I *succeeded* to get water absorbed as deep in the coffee particles as it will get, yet I saw zero benefits on EY and taste compared to yesterday’s long bloom. This may indicate these very deep layers that get wet last don't have time to participate much in the extraction anyway (I think deeper layers extract exponentially slower). In the fourth image, I show the fraction of light reflected at different wavelengths (colors) on my long-bloom brew (diluted to 1.43% TDS) compared to that of my short-bloom brew. The brews have different colors, indicating different chemical compositions: the taste differences don't seem to be a collective illusion 😬 In the last image I show two other brews prepared similarly; they look exactly alike, so the reflectometer data seems replicable.
Currently I think coffee compounds start diffusing into the interstitial liquid during the long bloom, and that's why EY is higher - thanks @samosmrke for the idea !
I just had a look at my Acaia blueprint from this morning's 3 minutes bloom V60 (see my previous Instagram post for more details) and water absorption by coffee particles does *not* explain the different taste and higher extraction yield !
Above, I show in black the water weight in my V60 vs brew time, and in red the expected floor in between pours from the rate of water absorption that I calculated with a normal bloom. As you can see, the valleys between pours do *not* align with it ! I made sure water had drawn down completely between every pour, so they should.
You'll notice that I made a small 22 grams pour right after bloom; I did so because if interstitial water was absorbed by coffee particles, I may be able to replace it with this small pour and measure a valley that hits the red curve better.
In the second image, I cut this morning's brew data between 45 seconds and 3 minutes, to see whether water absorption was happening at all from the interstitial liquid, and it matches up *very* well ! This means water absorption stopped happening as soon as water passed through the coffee bed, as @apaxos suspected.
Another puzzling thing is that my brew lasted for not just 2 minutes 15 sec longer than usual, but instead it lasted for another additional minute and a half, which I could only attribute to a slower flow of water through the coffee bed. I'll be very surprised if that was due to water being that much cooler.
These results are puzzling to me, here are my take-outs for now:
(1) Maybe this morning's brew was a fluke, and had a high EY because of a happy mistake I made ?
(2) Maybe another mechanism that I don't understand makes the longer blooms different with higher EYs and sweeter taste !
(3) We might be able to improve things further with a non-agitated 3 minutes immersion-style bloom where water absorption would still be happening during the full bloom.
Tomorrow I'll prepare the same coffee with my traditional method without a temperature probe in it (that created bypass water in my "traditional" pour over from yesterday), and then I can compare how permeable the coffee bed was, and whether I still get such a high EY.
This morning I just tried @umeshiso_’s long-ass bloom based on brew data I collected yesterday that seemed to indicate coffee particles needed more than 45 seconds to absorb their own weight in water (see my previous Instagram post for more details). I have not yet compiled my Acaia brewprints to measure LRR after the bloom, but the sensorial and refractometer results are already beyond my expectations. I brewed a Burundi coffee roasted by Andy Kires @canadianroastingsociety in May (vacuum sealed since them), and even recent brews I made with this coffee with my normal recipe were almost a full % lower in extraction yield ! 😨
With a 1:17 V60 and my EG-1 grinder at 7.0@700 RPM (burrs touch at 1.6), I usually had an extraction yield in the range 21.0-21.6% (this is one of Andy’s lighter roasted batches of the Burundi). With a 3 minutes bloom I obtained a 22.6% extraction yield with the percolation formula ! That can’t just be aging because I had much lower EYs just days ago.
The coffee tasted much sweeter and rich than usual, without any signs of astringency, bitterness or sourness. I recognized the complex profile of acidity and aromas of this delicious coffee, but the whole flavor profile seemed much deeper and more enjoyable.
When I compile my brewprints, we’ll see if I actually helped LRR go higher by the end of bloom, or whether this is a fortunate finding that can be explained by something else. I used my cork lid to keep the bloom as warm as possible, but I don’t know yet if that was useful.
I don’t want to take credit for this long bloom method. @umeshiso_, @tds_times_brew_mass_over_dose and @apaxos used it way before me, although I had never heard quantitative assessments of its effect !
Oh, and I just received my @kruveinc glasswares. So far I like them a lot !
#coffeeadastra #coffeescience #coffeegeeks #pourover
Are we not blooming our V60s long enough ?
Thanks to my Patreon supporters, I just received a second Acaia scale that I will be using to log the water in my coffee pot as well as the water weight out of my kettle in real time. I'm hoping that this will allow me to do a lot of interesting things, one of which to estimate a live coffee bed permeability during a brew and identify channeling, fines migration or erosion as it changes during the brew.
What I really did not expect is to already discover something super interesting after a single brew with the two scales. In the figure above, the line in black above shows the difference in weights measured by the two scales; it represents how much water is entrapped in the V60 as I prepare my brew. This is one of my typical two-pours V60 brews (for an example video of my V60 brews, see link in bio for my blog). At the end of the bloom (45 seconds), there is never any column of water above my bed of coffee, and the same is true at the end of the brew. At the end of my first pour, I always wait until there's just a small amount of water above my coffee bed.
You might know that a typical V60 coffee bed retains about twice its mass in water weight; approximately half of this is water retained between the coffee particles, and the other half is water absorbed inside of the coffee particles. We call the ratio of retained water over the mass of coffee the "liquid retained ratio" (LRR). My brew had LRR ~ 2.2.
What shocked me here is that by the end of the bloom, the LRR at that moment is FAR below 2.2 ! In fact, it seems like the LRR is an asymptotic curve with a MUCH longer characteristic time than I expected. At the end of my bloom, LRR is approx. 1.3, and LRR ~ 2.0 is only reached after 2 minutes !
This could mean coffee grounds are still absorbing water after 2 min, and deep coffee cells are gradually being unlocked for coffee extraction as water reaches them. If I'm right about this, we may gain a significant amount of extraction and evenness of extraction if we did much longer blooms of 2-3 minutes. This could however create new problems (e.g., low slurry temperature ?), so let's try it out and see what happens !
Thanks to the generosity of @whereisscottrao, I received a light reflectometer manufactured by @bionutrientfoodassociation that measures the fraction of light reflected from coffee beans or brewed coffee at 10 different wavelengths (i.e., colors) from the UV to the near-infrared !
I only started playing with it, but I’m hoping we can find out useful things about pour over brewing and roasting with it ! It’s still far from a spectrometer, but it’s 9 more data points than a refractometer !
I’ll be posting my progress and preliminary findings regularly on Patreon, which I’ll then use to write up detailed posts on my blog (link in bio). #coffeegeeks #coffeescience #pourover #coffee #coffeeadastra
Today I carried out a fun experiment by pure mistake ! I came back home to a full gallon of distilled water and couldn’t remember if I already put in my mineral concentrate or not. I tried to measure its TDS with my EC pen, but it had stopped working. I decided to be optimistic and brew with it; I thought I wouldn’t have opened the gallon if I didn’t put the minerals in, right ?
Well, turns out I had done just that, and brewed with distilled water. I used Andy Kires’ magnificient Ethiopian Nano Challa (oops !) ; I obtained almost the same extraction yield as my last brew with it (1.51% TDS at 1:17 for 22.7% EY, last time was 22.5%, this difference is within my manual imprecision margin). However, it tasted sour and shallow. This raised up a red flag so I spent 5 minutes debugging my EC meter, and finally found out that rotating the battery made it work again, and indeed it was distilled water.
I wasn’t gonna waste these great beans, so I calculated the volume of mineral concentrate that I needed for my beverage weight. I added it to my brew and quite amazingly it drastically improved its taste ! The sourness was almost entirely gone and I could taste a lot more of the usual taste profile. It was still noticeably worse than when I brew it with the correct water, but much better than what I obtained from distilled water ! Also, I found it interesting that adding my mineral concentrate had no effect on TDS.
This tells me there might be some truth to the claim that a small amount if bicarb reacts out unpleasant (and some sour) chemical compounds.
#coffeegeeks #pourover #coffeeexperiments #waterforcoffee
I previously had the intuition that brew water temperature would slightly affect drawdown time in a V60 because water viscosity depends on its temperature, and @jimseven’s similar comment in his recent V60 video prompted me to look into this dependency in more details.
I used data from IAPWS 2008 and Engineers Edge Machinery's Handbook to create the above figure that displays the dynamic viscosity of liquid water at atmospheric pressure versus its temperature. The variation in viscosity is *much* stronger than I expected; it approximately halves if you heat water from 20°C to 80°C !
Darcy’s law states that the flow rate in a percolation goes with the inverse of water viscosity, if everything else is kept constant. I used this to display the blue line above in the figure, which shows the relative flow rate for different water temperatures through the coffee bed.
I also used temperature logging data from my previous Instagram posts to place little circles and triangles at the typical average slurry temperatures when using a plastic and glass V60s, respectively (in both cases using water right off boil). The difference in slurry temperature in these cases should create a change of flow by 10%, i.e. the hotter plastic V60 slurry would draw down 24 seconds earlier than a 4 minutes brew with the glass V60. This is not a small effect !
For me this is yet another reason to use hot water, because I agree with @jimseven that a faster drawdown is good; it reduces the risks of channeling, and potentially allows you to grind finer, unlocking more coffee flavors.
#coffeescience #coffeegeeks #pourover #waterforcoffee
My post on coffee filters is now available on my blog (link in bio) ! In this new post, you’ll find a microscope imaging analysis of pore filters, and measurements of thickness, water tainting and water flowrates without coffee.
One thing that really surprised me is how the bleaching process seems to damage the uniformity of pore distributions ! If we can manage to brew coffee without the papery taste of unbleached filters, it’s possible they could help us achieve more even extractions !
I think this analysis is not complete until another practically applied counterpart where I will dial in each filter individually and use these theoretical results to interpret the differences.
My following blog post is also now available on Patreon, with a new tool to help you craft a mineral concentrate for brew water recipes that will help you create customized ionic compositions in your brew water, and allow you to start from soft tap water, reverse osmosis water or water bottles instead of distilled water. It is kind of a more detailed, but single-concentrate counterpart to the free water calculator redux that @baristahustle just released ! The equations behind this tool are surprisingly repulsive.
#coffeegeeks #coffeefilters #coffeescience #waterforcoffee #pourover
The other day @whereisscottrao brought me some delicious Ethiopian coffee roasted by Andy Kires from @canadianroastingsociety, and I noticed that the drawdown times were quite long, about 4:30. Then Scott commented that, in his experience, coffees from Ethiopia tend to have longer drawdowns.
I decided to look back at my last ~100 brews, and plot the drawdown time versus varietals, see how the Ethiopian heirlooms compare to the rest. And, as predicted by Scott, they have much longer drawdowns than average !
My best interpretation of this is the following: some varietals are probably harder (and less elastic) compared to others, causing them to shatter more while grinding. More shattering will produce more fines, and therefore slower drawdown times. The figure above likely contains a lot of intertwined variables that bias the results; for example, different processing methods, countries of origin and roasting probably also have an effect. If any of those hidden variables are overrepresented for one varietal over the others, then the data is biased (all "Heirlooms" in this figure are grown in Ethiopia, so that's one very clear bias). You might notice that my "error bars" (in red) have tiny error bars (in blue). This is not statistical heresy; the red bars are just measurements of the typical range (standard deviation) within a given varietal, not a measurement error. Therefore the blue bars are measurement errors on my estimated range.
Andy's Ethiopian had an even longer drawdown than my previous Ethiopians, but it also extracted A LOT more; I obtained 1.52% TDS concentration on a 1:17 ratio pour over, for an average extraction yield of 22.8% ! I usually only get such crazy numbers with Kenyan washed coffees. It also tasted phenomenal, and I suspect that this was due to a better roast development to what I usually drink. More development probably makes the coffee more glassy, causing it to shatter more.
When we have more data, I'm hoping we can use these variables to predict how we should adjust grind size ! That could potentially speed up the dial-in process !
#coffeegeeks #coffeevarietals #coffeeprocessing #coffeescience #pourover #canadianroastingsociety
I decided to move away from the SCA format for the flavor wheels I generated in my last post. Instead I defined categories in a way that made more sense to me, where the generally desired flavors are in the upper half, and those generally considered as green or roast defects are in the lower half. I also made the wheel look a bit more like a bean with its two halves, so we might call it a flavor bean ! Elliptical coordinates rock !
I updated the blog post (link in bio) with these new visualizations for the 5 varietals that were displayed in it, and I updated those for the 30 varietals and 14 processing methods (including high-resolution, vectorial PDF versions) on my Patreon (link also in bio) !
I hope you enjoy them as much as I do, and I should thank @firstbloomapp again for allowing me to do all of this !
Special thanks to @whereisscottrao and @alexcaza for the precious feedback !
#specialtycoffee #coffeegeeks #thirdwavecoffee #coffeebrewing #coffeescience #coffeemaths #coffeevarietals #coffeeflavors #coffeeprocessing #firstbloomapp
I‘m super excited to release my latest blog post (link in bio) about flavor trends of different coffee varietals ! This was made possible thanks to @firstbloomapp, who generously shared with me tasting notes from 1,500 coffee bags !
Please read the post for the full explanations and caveats of this preliminary exploration. I’m hoping this can help us treat coffee a little bit more like we treat wine, i.e. with great respect :) the figures above are an example of how well known varietals fare within the approximate SCA secondary flavor categories.
My Patreon supporters can also immediately enjoy my next blog post: a massive and extremely detailed technical review of coffee filters, includong a microscope analysis of pore distributions, measurements of thickness, flow rate and water tainting effect, with a set of practical recommendations. This was a *lot* of work, and the results really surprised me. I will start to vary the V60 filters that I used to see if my predictions can be used to acheive more uniform, potentially higher extraction yields !
#coffeevarietals #coffeeprocessing #coffeegeeks #coffeescience #firstbloomapp #coffeeflavors
2 thoughts on “Improving the Bloom of your V60 Coffee”