Jump to content
ADI Forums
Reiner

How long does it take for whiskey mash to ferment ?

Recommended Posts

I apologize if this question has already been asked before , but Im not familiar with this forums search engine . Anyways Id like to ask how long it takes for corn whiskey mash to ferment . Some sources say three days , while others say three .

Thanks ahead of time .

Share this post


Link to post
Share on other sites

two days, three days, four days, five days

depending on mash, temperature, yeast, conversion, etc., so your three days was a good ballpark figure.

  • reaction_title_1 1

Share this post


Link to post
Share on other sites

To echo Bluestar, there are a lot of variables, but the general range is 2-5 days. For example, higher temp will generally result in faster fermentation, but also more congeners, such as esters and higher alcohols. Another thing to consider is microbes other than your distiller's yeast. Lactobacillus, for example, takes longer than distiller's yeast to hit its stride, so tends to have a more impact in longer fermentations. Get a bench scale kit and do some test batches as part of your recipe development.

Share this post


Link to post
Share on other sites

My fermentations have yeast pitched at 78F and let them rise to 80F. All equipment is sterilized before pitching...a solid 5 days but I always give them 7. Adjust your PH, add nutrients & oxygenate.

Share this post


Link to post
Share on other sites

Depends on pitching temp, starting gravity, yeast strain, nutrient availability, ambient temperature, PH, available oxygen, mashing protocol (did you fuck it up?), exogenic enzymes vs endogenic enzymes (endogenic produce more unfermentable, or poorly fermentable sugars which = slower). Do you want some of that icky, bacteria action that happens after a ferment finishes? Makes for a good whiskey but you have to wait a few days!

I've found, all things equal, that rye ferments faster than corn. Exact same procedure for rye as corn and it ferments to completion a whole day or two more. Rye is done in 3 days, corn in 4-5 maybe? There's a lot of variables that effect time, and flavor.

Share this post


Link to post
Share on other sites

Does whiskey mash go bad if you leave it out too long after its fermented ? In other words is it safe to let fermented whiskey mash sit for two weeks ?

Share this post


Link to post
Share on other sites

Lacto is going to kick in once the yeast are done. Two weeks is probably pushing it IMO. You'll lose some yield for sure.

Share this post


Link to post
Share on other sites

This last winter I ended up storing totes for about two months between brewing and distilling. One of our totes got infected with something that made a VERY nice whiskey, which the lab we sent it to failed to identify in any useful capacity. Other than that, we got very lucky. We avoid deliberate lacto infection, so as long as nothing gets in accidentally we only have yeast in our mash. This is not to say I hated every day those sat, but priorities aren't always friendly.

On the other hand, we typically try for just over a week. We pitch on the light end for a more gentle ferment and to not risk overheating, and give a touch of extra time for slower ferments to finish. This last batch, every single tote is infected and giving terrible yield. Good sanitation practices makes the difference between indefinite storage and instant regrets.

Share this post


Link to post
Share on other sites

It depends a lot on your process, but if it needs to sit a while you can acidify the mash with acid. The lower pH can help prevent some things from growing in it. Keeping oxygen out / co2 in is also important.

  • reaction_title_1 1

Share this post


Link to post
Share on other sites

We're usually pretty much complete after 5 days, but sometimes we'll wait for seven days to let the mash fully ferment. You can also pitch your yeast at a higher temperature if you're looking for a faster ferment, but you may get some undesirable flavors. But hell, sometimes you'll get great flavors.

Share this post


Link to post
Share on other sites

I am a beginner but for barley mashes I do 7 days. I recently made a Sour mash bourbon that I let ferment for 4 weeks. The bourbon it made was amazing.  And if I am going to be away I will set a moonshine corn mash fermenting for up to 4 weeks.  If I get a Lacto I run it anyway. Makes great whiskey but I dont do it deliberately.  

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×