Adjusting Extraction for Immersion Brews

Coffee preparation techniques besides espresso like pourover.
ShotClock
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#1: Post by ShotClock »

Wondering what is the optimal way to adjust extraction for immersion brews. I've been trying out a very nice Colombian, but get a persistent over extracted note. I've tried grinding coarser and dropping the temperature, but end up with something that's watery and still has the bitter finish. I don't think that this is the coffee, as I've had good brews from it in the past. I'm using the aeropress with prismo, 2 minutes steep with no agitation, grinder is a monolith flat SLM.

Chili Palmer
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#2: Post by Chili Palmer »

You didn't mention the roast level or dose amount. Darker roasts should use lower temp. More immersion time shouldn't hurt and should help the watery-ness.

I agitate (stir) using the paddle for consistency. What's the reason you don't stir?

But yes, I'm always fumbling about to figure out the right grind size. With my MC5 it doesn't seem to matter as much anymore! Everything that comes out of it is yummy.

But now I'm over-caffeinated.

ShotClock (original poster)
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#3: Post by ShotClock (original poster) »

The coffee is Indestec from steady state roasting. I'd say that it's fairly light, although not extreme. I'd guess it's dropped around 15F past first crack, to my rather untrained eye. Not normally something prone to getting over extracted.

I don't agitate in the thought that it will reduce the speed of extraction, and make things a little less time sensitive. Just found it to be easier to dial in. I tried temperatures from 98C to 95C, but couldn't get rid of the bitter note.

Chili Palmer
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#4: Post by Chili Palmer »

Sounds like you are in the right temperature range. Maybe increase grind size?

Here is another thread that may help. It's pourover oriented, but seems like there are clues...Pour-over, finer grinds / higher extraction and less complexity and clarity

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invisibro

#5: Post by invisibro »

I have a max with SLM burrs. They're amazing at espresso, not bad at pourover (compared to brew-dedicated burrs), but you have to work around them.

Is it a natural process by chance? I've found the amount of fines kind of stays kind of high even if you go really coarse. This might be why you're getting bitter notes even though you're grinding coarser. I'd either go with a brew method that works better for those beans+burrs or if you're dead set on immersion, grind finer and try to speed up the extraction time - probably Hoffmann Clever method but experiment with starting drawdown earlier.

ShotClock (original poster)
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#6: Post by ShotClock (original poster) »

Thanks for all the tips guys. Not a natural, this is a somewhat experimentally processed washed Colombian, from Diego Bermudez of Luna/Letty fame. Very clean, fairly light, although not extreme in this regard.

I've made some good progress by cleaning the wipers on my grinder with a toothpick (from the chute - not disassembled), and then shortening the steep by 20s (now only 1:40). Not sure which was the culprit, but I got a nice fruity, sweet brew today with 97C water and my original grind setting (slightly less then 180 degrees away from an average grind setting for washed medium roast espresso). Slight hint of bitterness on the finish, but I'll experiment with shorter steeps next time.

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invisibro

#7: Post by invisibro replying to ShotClock »

Glad you're making progress. When I said my experience with SLM burrs is that they produce some fines I didn't meant to imply only with natural processed beans.

The wipers do gather a decent amount of coffee - I've found that removing the magnetic chute and holding a vacuum to the exit while running the grinder clears that out rapidly. I'll have to try that on mine and brew another pourover to see if it mitigates the fines that I noticed the last time I tried a brew.