How to Taste Coffee

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#121

I have been doing this too.

Perhaps later I will try something else - but for now declining ROR


#122

So 448F is 230C for first crack - based on inlet temp.

Whereas it seems I am getting it about 200C based on exhaust temp (I would love to have inlet and exhaust temp in my machine :smile: )


#123

So do you think that is that because the cracks are hard to hear - or because you are not getting all the beans to 1C???

This is pretty much the same for me it seems (that I think) I can hear a few cracks - but not many - and they also seem pretty quiet.


#124

I’m just not a fan of the cold-extracted stuff. To me it is not really coffee in the normal sense - as it is not brewed (brewed = heat). So it has a totally different flavour profile.

I’m happy if other people like it but not my thing…

Though perhaps using ultrasonics for cold brewing could extract more flavour and make a more interesting drink :wink:


#125

Oh yea sry I meant to specifically mention that as well. The decibel range of 1C is directly proportional to how much heat/pressure is within the bean or how hot you get to and go through 1C. Your Pro version seems to hit the same temps as drum roasters, I guess that’s how it was designed. However since you can let the machine do all the work you can pretty much copy a drum roast profile directly or do a linear function from 300-400*C or 150C-250C and keep it around 5min like Jen Apodaca does at Royal Coffee. Once you find a base, or a profile that gets you the flavor profile you like, then you can make real, big, changes and see how that affects the gamut…if that’s how you want to go about it. From reading Jen’s notes, I see that she only moves/pulls down the belly of the profile on her linear graph and notes different flavors. I don’t have that kind of palate or beans, so I’m not able really judge those profiles. https://royalcoffee.com/crown-analysis-cj1203-ethiopia-kochere-alemu-bukato-double-washed-crown-jewel/ dropping in 4:45 with a dev time of 1 minute, that is not abnormal and I see why she would develop for so long. My reasoning, is that because the pace to 1C is so fast spending enough time for the actual bean to catch up and spend time in the high heat environment gives enough time for those necessary reactions (breakdown of sugars etc don’t mind the chemistry) what’s important is that there is enough time for those green flavors (underdeveloped) to move to fruit flavors (developed), without overshooting and baking everything out, I think flowers may be a cause of speeding quickly through the green and not allowing them to volatilize out of the decomposing cellular matrix. I think she is managing to get development because of her dip in the fan allowing for conduction heat to take place, which also slows down the temp increase, hence giving enough time to develop. I also think that the team there may be drinking those cups immediately because in my experience those flavor notes are really apparent immediately after I roast. I have not done much testing of cupping literally right after roasting but in time I will. Now I am (continuously) working on apply different heats/seeing if previously good profiles work with a new set of beans from the same region, from a different year. But again I digress and I hope that this has not been too confusing or too much at one time.


#126

Heh… interesting - brewing and heat. I dont think of the process as brewing, I think of extraction … and temperature is just one variable, so why not extracting at low temperatures? Sure it extracts in a different way and creates a different flavour, and sure it may not be liked by everyone … but … From my experience not nice cold brew is usually the one made by leaving the coffee in the cold water for long period of time … sort of slow immersion style :slight_smile: … but a cood drip version creates very clean and rich tastes (and also clean transparent looks). I have tried also different temperatures, using low pressure and so on … but the drip version is one I like the best.

Using ultrasonics to enhance enxtraction sounds great, Though starting with a very uniform particle sizes (that 200um or less) helps a lot with pushing the espresso extraction to higher TDS, so try that first I would say ;))

Lab sieves are really good though expensive idea, but I would say having some “vibrator” (not sure what is the propper name) to speed up the sifting would be even better … For me its not a problem of dose, its a problem of speed and time it takes to sift … which adds something like 15 minutes in my case. And I think its too much for regular use.


#127

Yes I was just using “brewing” as a way to group coffees extracted with heat. And I was copying the (hopefully) common usage of this use of the term…


#128

I haven’t done so much experimentation - but I liked the drip the best too.

I guess my “brew” point is more that all of the “hot” coffee extraction methods are in a similar spectrum of taste - as heat extracts extracts particular flavour compounds from coffee.

CORRECTION: The next paragraph contains INCORRECT information. (Further reading) indicates that cold and hot extraction extract almost exactly the same compounds from coffee. The reason that cold brew is easier on the stomach is (probably) because the heat (of hotter extractions) actually changes the compounds after it has bean extracted (Basically the heat causes formation of more sour and bitter compounds which are harder on the stomach = same reason darker roasts are harder on the stomach)

Cold extraction completely misses extracting some of the “hot extraction” compounds (including some that can be hard on the stomach for some people). And because of this it has totally different profile of flavour (and is easier on the stomach). Which means the I tend to regard it as a “different” type of drink - rather than a just a variation on extraction (because the flavour profile is so very different IMHO :slight_smile: ).

And I do wonder what effect sonification (or a rotor-stator homogenizer) would have on cold extraction - as they should extract a lot more flavour compounds. So perhaps that would push the taste profile back in the direction of a hotter extraction (but maybe with a cleaner or purer flavor???)


#129

The idea of getting used to a “standard” or “base” and then working with variations is exactly what I am trying to do - just seems to be a logical to me.

Though there is also something to be said for madly trying lots of different profiles until I find something I like. But then I would probably treat that as a base and try a bunch of variations…

Interesting that you say the exhaust temps on my machine look more similar to drum roaster temps. This is what I had suspected/expected (hoped for) - so it is good to get confirmation.

I will investigate Jen’s stuff…


#130

Thanks Deven!

I never thought of this before but it makes perfect sense… If there is more pressure in the bean - because the bean gets to 1C faster (and at a higher temp) - then there is/was less time for water/CO2 to escape (than there would be in a slower/longer roast) = the crack will consequently be more violent and louder…

So I will try some shorter roasts to get a better idea of what 1C sounds like…


#131

Roast development (and underdevelopment) is an interesting area to me. And it seems that it would be helpful to measure it. It seems that the best way to do this is measure the colour of the outside of the beans, and compare it to the ground beans. The colour variation gives a measure of how much lighter (less developed) the inside of the bean is.

And it seems that I am saying “it seems” too often - well it seems to me that it seems to be the case - so it seems :wink:

An interesting video from Mill City on roast colour:

It’s seems to me that this would be a very useful tool for testing roasts quantitatively - along with testing the TDS of the brewed (@pavel = extracted :slight_smile: ) coffee. It seems (again) that it would be very helpful to learn when the roast was underdeveloped and by how much when you are learning to roast. So it seems to me that this would be very helpful tool for learning the effect that different profiles and roast times actually (quantitatively) have on the roasted coffee beans :smile:

Unfortunately coffee spectrophotometers are expensive. Though cheaper options are becoming available. I had been looking at the Tonino - which is “only” $600 - however it appears it is only designed to test ground coffee (not beans) - so it kind of misses the point!!! Other than that there is the Lightells (price seems to vary from $1200 to $3000 depending where you look). And recently a new option from Mill City the Roastrite color analyzer for about $800 (there is also a $1200 “Bigfoot” version).

And of course there are the larger bench models from Agtron etc - but these start at over $3000…


#132

Dont take me wrong, I understand what you mean. But what I am trying to say is, that there is only difference in changing some parameter of extraction … you can do immersion brew at say 92C, but you can do also say 80C and its different but still coffee right? But you can also do immersion brew at 60C (I tried :)) … so why not 40 or 20C? What I mean to say is - you said there are brew coffees at high temperatures and cold extracted as a different category, but I say there is a gradual transition with no clear separating line … between the unusable boiling and freezing of water :))

Btw … have you tried warming the cold drip to above 40C ? Its also quite interesting to try. Drinking the cold drip warm or hot :wink:


#133

My apologies.

Looks like I was mistaken about the different extraction profile for cold and hot brew methods. I shouldn’t believe everything I read!!! (I will add comments to the earlier post explaining that I was wrong)

The differences in the hot brew (more bitter - harder on stomach) are likely caused by compounds breaking down from heat - so basically the heat will cause more bitter flavours to form.

I just found a video with (infrared) spectrographic analysis that shows that cold brew and hot brew extracts pretty much exactly the SAME compounds from the coffee. I also found various other articles that basically agree with the video.


#134

So to explain how I got misled about the “difference” with cold brew extraction. Not so much to “defend” myself - but more to show that there is a lot of conflicting (and plain incorrect) info out there about cold brew…

If you search google for something like “cold brew easier on stomach” you will get a lot of articles that explain (incorrectly) how there is much less acid in cold brew. Turns out this is false as per the video with the spectrographic analysis. So it also turns out that the (relatively few) cold brews I have drank tasted milder - so silly me I believed that this (incorrect) information was correct. So what was the real reason that the cold brew tasted different? I suspect it mostly came down to the particular (milder tasting) coffees that were used to make the cold brew (OOPs…).

So going back to that video where they compared cold brew and hot brew using the SAME coffee. They found that the extraction produced pretty much the exact same balance of compounds (though it might be stronger or weaker - the ratio of the compounds was very similar). So if cold brew changes the taste it is for other more subtle reasons - not 50 or 60% less acid as is touted at many sites (which is just plain untrue) Another thing that many cold brew articles say is that cold brew has less caffeine = also not true as shown by spectrographic analysis.

Also another thing that is not true is that lower acid coffee is “easier on the stomach”. Or if it is then it is not because of the lower acid content - coffee is not particularly acid anyway. And the variation is well within the range of many common foods that don’t upset the stomach “because they are acid” (the least acid is similar to potato and most acid about the same as a banana). However there is probably enough anecdotal evidence that cold brew is easier on the stomach - but it is just not caused by lower acid and/or lower caffeine :slight_smile:

And if there is a big “difference” in flavour it is more likely to be from choosing different beans for cold brew… (so not comparing apples to apples). Of course choosing a different bean/roast for cold brew makes perfect sense as it probably works better with different beans than you might use for espresso . So why does cold brew taste smoother, it seems that it may have more CGA (chlorogenic acid) than hot brew. This is because CGA is easily broken down by heating (into other acids) which are more bitter - so this may contribute to why people say it is smoother. So in this case the heat tends to break down the CGAs AFTER extraction - which does not happen in cold brew (because there is no heat…).

But why is it easier on the stomach? Hmmm not so clear. So why is coffee (or something else harder on the stomach) well the reason is (almost certainly) because it stimulates the secretion of stomach acid (Note: anything that is actually acid enough to irritate the stomach would probably be close to impossible to eat or drink and would cause serious damage to your mouth and throat). So what compounds in the coffee cause you to secrete more stomach acid (unfortunately there is a load of misinformation on this). Well I saw several articles that said that more CGA made it easier on the stomach - this is untrue as CGA actually stimulates stomach acid secretion (though CGA is a powerful antioxidant and is probably good for you). Other articles say that the “reduced caffeine” in cold brew reduces stomach acid. While it is true that caffeine stimulates stomach acid - this is not the cause as cold brew does not have less caffeine (back to that spectrographic analysis).

What does seem plausible is that cold extraction can increase increase the extraction (of small amounts) of other compounds like NMT that actually suppress secretion of stomach acid. Though I did see one article that (incorrectly) said that NMT increased stomach acid. Other articles suggest anecdotally that concentrations of some terpenes (that could be irritating) could be higher in a hot extraction.

Anyway it just goes to show that it is easy to draw the wrong conclusion… As there is a lot of (mostly uninentional) misinformation out there about cold brew :blush: and probably about other things :wink:


#135

Great post! I have to say I did not know it may be almost the same - my feeling about it is that temperature may change the rates at which different compouds dissolve so the ratios may be different (just my feeling about it …). BUT - and thats why I reacted to making it a different category - I believe that if something is soluble in water, it will eventually dissolve … though it may take more time in colder water … I think thats why we use hot water because its fast :))

Regarding the differences in taste, from experience I would say there is two types of differences … one is real and one is “virtual” … the cold drip really tastes softer, more round … my description vs pour over of the same coffee is that it is both stronger, richer, and not having sharp harsh spikes in the taste … its like its been sort of polished. Yet the taste profile is quite the same to pour over in fruits florals etc… not sure what makes it be that way, but in drip its very very clear so part of it might be that there are verly little undissolved solids, and also there is quite a lot oils (you dont see them but try to freeze it and you will see) … way more than in pour over with paper filter.
Than there is that virtual difference and that is I believe caused by us drinking it very cold. I did try to warm it up to simillar temperature as pour over, and the other way around … cooling the pour over to the same temperature as cold drip … and … well just try it :slight_smile: I think like 30% of the effect is in the temperature.


#136

I guess @deven.patel411 could clarify this from chemistry POV - if the solubility in water can change a lot with temperature (thus making some compounds almost not present at some temperatures) of it is just variation in ratios, or same ratios … I only used my intuition on this one :slight_smile:


#137

This was exactly my feeling too - and it appeared to be confirmed by differences in taste… Which was why I was ready to believe the “common knowledge”

BUT the science seems to say different, look for the extraction graphs at 13:30 (the rest of the video is mostly about safety = how not to grow bugs when cold brewing)


#138

This one makes perfect sense as cold reduces taste perception - and is recognized as a good way to hide bad flavours in cheap wine :slight_smile:


#139

Thank you for the video … interesting to see those graphs … really looking very much the same.
Just a question - do you remember what method was used here for cold brew? Was it cold drip or batch/immersion brew?


#140

As far as I can tell all the info given is Hot and Cold…