Making Coffee Concentrate - Page 2

Coffee preparation techniques besides espresso like pourover.
DamianWarS
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#11: Post by DamianWarS »

I divided a 20g dose for a pour-over into two 10g parts. The first 10g I did as a regular pour-over with like a 1:17 ratio. I then took that brewed coffee and used it as my brew liquid for the next 10g. my intention was to try and get a concentrated brew without further reduction steps. I never had a refractometer to measure the TDS and I'm still interested in what sort of impact it had but the resulting brew was very astringent and I wouldn't recommend it.

when it comes to reduction using distillation methods like in a vacuum and boiling it at room temp or doing a freeze distillation, or double freeze distillation I would think you would be sacrificing the volatile compounds like the aromatics simply because of the time involved in the distillation process. Even if you flash froze it with something like liquid nitrogen the distillation process itself is still too long to keep the volatile stuff. You would have to have a high extracted espresso and then flash freeze that and when you want to use it pour hot water over it to melt the high extracted shot, something like what Cometeer does.

With a high precision grinder and something like a Decent espresso machine, I think Rao/Perger "et al" have reached extraction levels breaching 30% without bitter/astringent flavours (but I'm not sure what the ratio was). for a regular 2:1 ratio shot with a 30% extraction yield, it would be a TDS of 15%. to achieve a 20% TDS and keep a 2:1 ratio you would have to have an extraction yield of 40% which probably is beyond the limits of this discussion. 30% extraction is probably the highest you can achieve and it would require a lot of fussing to get to that level. But even with a more obtainable 25% extraction, if you flash freeze that it would be the most effective way to keep a coffee concentrate whilst keeping the volatile compounds. You just need to get some liquid nitrogen and be able to pull consistent high extracted espresso shots.

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Jeff
Team HB

#12: Post by Jeff »

Alas, no longer in business, but Sudden Coffee was one of the few "good" instant coffees I've tried.

There's a good introduction and description at https://sprudge.com/kalle-freese-dried- ... 95851.html as a starting point.