So I’ve done a few batches with the Angel Yellow yeast with glutinous sweet rice and most of them turned out darned decent as a shochu/neutral. So I decided to try my hand at doing a honest to goodness koji based fermentation. I figured since it was my first time I would make some sort of mistake. However the mistake that happened was something almost unbelievable. I have tested it a couple of ways (including a small distillation run) and my current batch of “sake” is sitting at over 25% abv BEFORE distillation! What magic is this?
My process to get where I am:
Milled sweet glutinous rice to a near flour
Add boiling water just enough to saturate it
Cool down to under 35 C
Sprinkle koji spores on the top
Stir gently once a day for 3 days
Add lalvin ec1118
Stir gently once a day for 3 days
Add more water
Let ferment till no more bubbles
Did I just get a mutant strain of ec1118? Or is koji somehow giving it a super power by doing parallel fermentation?
I’ve measured via refraction (I know it is not accurate because it is a parallel system).
I’ve measured by taste (and it sure seems VERY potent for a wine)
I’ve measured by my lil air still and it really seems like as if it has to be at least in the upper 20s to get the yields.
Once I do the full remaining 5 gal in the still if this is truly what I’ve measured perhaps I will make up a tutorial/recipe.
What ratios of grain did you use, high 20s is high, like really high?" you can pick your nose and you can pick your friends; but you can't always wipe your friends off on your saddle" sage advice from Kinky Friedman
25%abv does sound high but the koji converts the starches to sugar slowly and the yeast convert sugars to etoh - such that you never have a high OG - or more accurately "high osmotic pressure" which causes yeast cell walls to rupture. It's similar to step feeding honey in a high abv mead.
It's not necessarily the high abv that kills the yeast it's the initial high gravity that harms them - i'm sure they are killed at a certain ABV in any case but you can get higher ABV by step feeding which is what the koji does...
Cheers!
-j————
i make stuff i break stuff
water into whiskey into water
just getting started in home distilling - been drinking for decades
16g copper pot still, 10l alembic, and a column or two
————
For a reference point when using angel yeast I expect about 0.64 liters of ethanol from 1 kilogram of rice. With your quantities that would be a little over 20%.
If the fancy rice has more starch and/or sugars than my cheap big box store rice 25% isn't that big a stretch.
Was your rice marked with nutritional data that gives startch and sugar content?A wise man never makes a mistake. He has many learning experiences.
If you add just enough water to saturate your grain, then yes 25% sounds about right.
Most grain bills are what 2#/1 gallon? Sure is a good bit more watery than what you're making it sound like you've got."In the silence of the study one can discuss theories, but only in practice one becomes an artist" - Meunier
Are you only measuring using a refractometer?
I guess measuring density doesn't work when you have such a high ratio of solids in the mash. Maybe it affects refractometer readings too?
Presence of ETOH definitely affects refractometer readings.. I find with koji and step feeding you need to go with the volumes to estimate final abv. If you're really interested in the final abv you might need to use the TTB method or similar to determine it.
You could just use a certain amount of rice and/or other grain (eg; Approx2#/gallon of water) and shoot for ~10%'ish - ferment / strip run -> spirit run...
Two 50# bags should net you somewhere in the range of 2.5 gallons after cuts give or take...
If you cultivate your own koji you can use rice, barley, wheat, etc as your substrate to grow it on...
Cheers!
-j————
i make stuff i break stuff
water into whiskey into water
just getting started in home distilling - been drinking for decades
16g copper pot still, 10l alembic, and a column or two
————
Post time 2022-10-11 19:46:02
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