What Are the Thresholds of Reliable Tasting?

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drgary
Team HB

#1: Post by drgary »

In an earlier thread on the quality of grinding with or without a hopper, some differences of opinion emerged about the thresholds at which one can discern tastes. I'm starting this thread because I believe the questions there are worthy of investigation but are better treated on their own. From that other thread, here are some questions that emerged for me. I expect that most of this is already known and would appreciate some guidance and resource suggestions. Please feel free to include your own questions or considerations.

1. Does one acquire sensitivity with familiarity?

2. Does such acquired sensitivity increase in a predictable way?

3. Does that sensitivity fade over time and if so what causes its decline?

4. Once one has learned to name flavors and other cupping aspects, how much does this shape what is perceived or missed?

5. At what point do expectations mix with perceptions, especially when "squinting" for distinctions? Has there been any research on this?

I'll add that memories are constructed after the experience has been registered through one's senses and symbolized in words and context. Therefore you're more likely to expect wonderful, nuanced flavors from top gear fed excellent coffee and operated by a skilled barista, and you may even notice more of the nuances of that cup than one handed to you at a highway rest stop.
Gary
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What I WOULD do for a good cup of coffee!

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peacecup

#2: Post by peacecup »

Nice try Gary, I thought of starting a thread myself. Tasting science is probably a lifetime scientific pursuit, however, so no answer is likely to be forthcoming. From the previous thread, it appears Jim S is familiar with the science, and of course he has a lot of coffee tasting experience. I'll look forward to seeing if he or others reply.

A more realistic objective for HB might be a set of taste test methods that people could follow if they wish to carefully compare machines, methods, etc. As Jim notes, and I have often tried to articulate, honest comparisons should be done with blind taste tests. I'm sure any review of tasting science (or whatever it is called) will back this up.

The reason objective taste tests are important, in my opinion, is that people tend to spend a lot of money on this hobby. Would-be home baristas are entitled to objective information from HB taste tests, because HB is one of the premier sources of information for the hobby.

PC
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Hand-ground, hand-pulled: "hands down.."

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yakster
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#3: Post by yakster »

Interesting topic. I was just reading about the Just Noticeable Difference and Weber's and Fechner's Law in the Coffee Cupper's Handbook last week by the pool and following this lead, I found two web resources that might be relevant to this thread:

Intro to Sensation and Perception from the Educational Portal Academy which talks about perception, Fechner's and Weber's Laws as well as how sensations below threshold can affect you (subliminal) as well as sensory adaptation where you can tune out repetitive perceptions and selective attention where you can focus on certain perceptions.

Wikipedia article on Weber - Fechner Law explains these laws and goes deeper than the Coffee Cupper's Handbook to explain that perceptions are more likely to follow a power law than a logarithmic response, but either way, it takes a multiple or power change in concentration of a stimuli for each increasing Just Noticeable Difference threshold.

I think that these are pretty basic and generic and it would be interesting to see more specific studies regarding taste and aroma perception.
-Chris

LMWDP # 272

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bean2friends

#4: Post by bean2friends »

I may be wrong, but I suspect someone like Thom Owens at Sweet Marias is using some kind of reference kit for smells and tastes. I mean what's the difference between fig bar and whole wheat fig bar? I also think I'm jealous of folks who have better tasting abilities than I. The more I roast and brew in different fashions the more flavors I discern. What's most important to me is I know what I like. Also, I think the more coffees I try, the more I'm able to get different flavors. Variety, it turns out, is the spice of life.

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drgary
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#5: Post by drgary »

peacecup wrote:Nice try Gary, I thought of starting a thread myself. Tasting science is probably a lifetime scientific pursuit, however, so no answer is likely to be forthcoming. From the previous thread, it appears Jim S is familiar with the science, and of course he has a lot of coffee tasting experience. I'll look forward to seeing if he or others reply.
Jack:

I'm not trying to get a comprehensive answer, of course, but get a sense of how to start to think about this subject with regard to coffee and espresso particularly. Yakster (Chris) has offered some good, basic theory, for instance.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

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another_jim
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#6: Post by another_jim »

This is a surprisingly easy question to answer, although you'll need to free up a weekend. You use a sequence of triangle tests, i.e., picking the odd sample from three blind samples of which two are identical and one different (if you want to be even more sure, use five samples grouped two and three, and pick the group of two, which is a 10:1 shot at random).

Use two coffees from the same region. Can you tell them apart in a triangle test? Then take one coffee, and a 50/50 blend of the two coffees. If you still can tell them apart, drop to 25/75 blend. Keep going until you can't tell them apart (how far will depend on how different the coffees are). Staying at that ratio, practice tasting them a while (with IDs). Eventually you will be able to tell them apart. If you want to learn what is distinctive about the coffees in a particular region, do this style of learning. Once you can reliably distinguish the different coffees within a region, you have a mental grid that does that region justice. Personally, I'm good at African coffee, and getting much better at Centrals, and still pretty hopeless distinguishing South American coffees

Once you understand your palate's limits, and how they can be improved with practice, you'll lose interest in these princess on a pea discussions. You spend time roasting and tasting coffee, so of course you enjoy them, and of course you can distinguish the good ones form the bad ones -- I've never met any coffee hobbyist (with one very odd exception) who can't. You don't need a magical palate; you just need become experienced. The important thing is to gain that experience by frequently testing both the coffees and yourself.
Jim Schulman

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drgary
Team HB

#7: Post by drgary »

That's what I was hoping for, Jim, but didn't know how to ask, a primer on developing coffee knowledge and learning one's palate by taste. Thank you.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

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TomC
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#8: Post by TomC »

Great thread idea. As soon as I saw it posted I was going to beg that posters who share any input at least state whether they were sharing subjective opinions or objective facts that can be backed up with references.

More importantly though, is that Jim made it easier for the rest of us by eliminated a good deal of the mental hoops we sometimes slog around in and just laid out an actual exercise that teaches the point. I appreciate that and may try it soon.

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the_trystero

#9: Post by the_trystero »

another_jim wrote:This is a surprisingly easy question to answer, although you'll need to free up a weekend. You use a sequence of triangle tests, i.e., picking the odd sample from three blind samples of which two are identical and one different (if you want to be even more sure, use five samples grouped two and three, and pick the group of two, which is a 10:1 shot at random).

Use two coffees from the same region. Can you tell them apart in a triangle test?
Thanks for suggesting the triangle test for this discussion, especially the mod for doing it with 5 cups. I sometimes doubt myself with the 3 cup method and figure I'm just getting lucky. I think I'll switch to the 5 cup method.

Personally I'm a long ways from detecting the differences in two coffees from the same region and of the same bean variety.
"A screaming comes across the sky..." - Thomas Pynchon

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rpavlis

#10: Post by rpavlis »

There are many chemical structures that create different types of taste sensations for different people. A classic example is certain thiourea derivatives--some people are unable to taste them and others find them intensely bitter. It appears to be the case that the reason some people like certain foods and others detest the very same food is genetic variation between people.

For this reason one should never assume that because someone who is supposed to an expert says something tastes great or that it tastes terrible that others will agree!

It is a serious mistake to think that because an "expert" thinks something tastes wonderful that you will automatically find it wonderful too!

Remember you are the only expert about how something tastes!!!!!