How long to allow fermentation?

[HappyHighwayman]

How many days before a typical 5 gallon mash has the max alcohol? Is there a point where it's still bubbling but no more alcohol is being produced?

Or is it best to allow for a full 7-10 days for the most alcohol?

The book I have (and granted it's for a 1 Gallon mash I times it by 5) says 2-4 days for fermentation!

Any thoughts?

[ShineRunner]

Check it with a hydrometer. That's the only way to know for sure.

Be patient and let it stop bubbling. Don't rush these things...

[DarthVapor]

Hi HappyHighwayman,

Short answer: it depends on what your fermenting and what the variables are.

Long answer: fermentation greatly depends upon several interconnected variables such as the type of fermentable (sugar, molasses, all-grain, malt extract, fruit juice), water profile (hard/soft, mineral content, pH and chlorine levels, etc.), yeast strain (lager, ale, wine, turbo, specialty), starting gravity and temperature range. I've had high gravity rum washes (SG 1.100 or so) take up to a month to ferment down to TG 1.010 and have also had mid gravity all-grain mash (SG 1.059) ferment to dry (TG 0.998) in as little as three days.

This is also why keeping logs is really important!

May I ask you what is it that you are fermenting?

[HappyHighwayman]

Awesome. I'm not in a rush.

[HappyHighwayman]

I have some bourbon wash...5 gallons...10 lbs cornmeal, some rye berries and wheat flakes. And a sugar shine, 9 lbs sugar + 1 lb raisins.

Both using ale yeast.

[BoisBlancBoy]

If it's bubbling it's not done. The yeast are still converting the sugar to alcohol and expelling CO2 as waste. Like others have said there are many variables that contribute but don't rush it, wait till things have gone inactive and let it settle out.

[HappyHighwayman]

Thanks a lot


I'm learning so much from this board.

[skow69]

wait till things have gone inactive and let it settle out.

+1. When it clears it's ready to run.

EDIT: If you don't have one ready when you want it, that just means you need more fermenters.

[bilgriss]

If you don't have one ready when you want it, that just means you need more fermenters.

This is a fact.

[rgreen2002]

wait till things have gone inactive and let it settle out.

+1. When it clears it's ready to run.

EDIT: If you don't have one ready when you want it, that just means you need more fermenters.

+1 to everything about this...!

I find if you don't let it clear then you will get a "yeasty" flavor in your distillate. I've let things go for weeks and know some here have gone longer.

Get another ferment started... then you can keep moving!

[Kareltje]

There is no such thing as a typical 5 gallon mash.
It is not the size that makes the mash, it are the ingredients, the treatment, the yeast, the ambient temperature etc.
As is already told.
Best advise: make another ferment to keep you busy. And next week another.

Or still the batch and referment the spent lees.

[HappyHighwayman]

So typically a longer ferment is only good then, there's no downside to a multi-week ferment?

[cranky]

So typically a longer ferment is only good then, there's no downside to a multi-week ferment?

The only problem I see with a long ferment is if you don't sanitize well or don't air lock it you may get an infection. Sometimes infections are actually a good thing. I never run anything that hasn't fermented for at least a month, most of my stuff ferments much longer than that. I ran off some rum a while back that had sat infected for 4 months and had a thick white fuzz on top and it was fine, I've let cider sit for an entire year and have blackberry must I fermented 3 years ago sitting in a half full carboy the whole time with no problems. If doing a long ferment, airlocks are the most important thing to keep the bugs out. I did almost lose 10 gallons of cider to the vinegar flies last year. After 6 months of sitting with an ill fitting lid I opened it up and found 3 inches of mother on top. I distilled it anyway, only saving 2 quarts of the vinegar. It still distilled fine and the vinegar is the best cider vinegar I have ever used.

[rgreen2002]

I never run anything that hasn't fermented for at least a month, most of my stuff ferments much longer than that.

You sir are an amazingly patient man!

[HappyHighwayman]

I think I'll do as suggested and wait until they stop bubbling and just make more in the meantime.

[mulligan]

A long ferment may contain a little more fusel oils which would in theory lead to hangovers, but sensible cutting out of tails will negate this

edit : short version is don't think the stuff with 15% never mind 5% alcohol at the end is like beer. Tails taste awful and will make you hate life the next day. Keep them for re-distilling or dump them.

The best part of this hobby is good tasting stuff and a clear head and happy gut the next day. It makes you feel insulted about what we get sold.