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Stalling yeast

PostPosted: Mon Apr 29, 2013 8:17 pm
by Distillingchris
I think my fermentation has halted, seems to have been stuck on about 1.15 for a few days now, am I being inpatient ? Or has it stopped fermenting and is there a way to start it back up again or was I being unreasonable thinking my corn, barley rye whiskey would ferment below 1.000 ?

Re: Stalling yeast

PostPosted: Mon Apr 29, 2013 10:18 pm
by Almanac
If the wash tastes sweet then it has probably stalled. One of the most common causes of a stalled wash is if it has become too acidic. If the pH get down below 3.5 the yeast will stop all activity but this can be corrected with a load of bicarb.

Check the pH and if it is too low sprinkle in about 2 oz of bicarb gently, if you chuck it in all at once the wash will foam up and may overflow. Then recheck the pH. If you get it back to over 4.5 it should restart but you'll need to keep an eye on it.

Having said all that you have to take into account that with an all grain wash you shouldn't expect any more than about 7-8%, after all you're making beer and distilling it ;D

AM 8)

Re: Stalling yeast

PostPosted: Mon Apr 29, 2013 11:24 pm
by scarecrow
chaslam07 wrote:seems to have been stuck on about 1.15

I gather that's 1.015. If so I wouldn't worry about it. Like aidanmac said, if it ain't sweet, it's done.
My AG batches sometimes finish at 1.010 or higher. I just live with it. Could be many factors causing it. Low temp is notorious for stalling batches. Low pH at the start of the ferment will delay start up. Also, pH will drop during the course of the ferment.
I'm not a believer in adding bicarb. I don't like the "soda" taste it imparts, but YMMV.
What SG did you start with?
What is the temp of your fermenter?

scarecrow

Re: Stalling yeast

PostPosted: Tue Apr 30, 2013 7:33 am
by Almanac
I see from your original recipe your grain bill consisted of 3kg of Maize, 450g of Rye and 320g Barley.

You posted your OG as 1.050, in your original recipe.

If fermentation was complete you should have a gravity close to 1.000 giving a yield of 6.45% but if your gravity is still 1.050 then there may have been no fermentation at all.

The Rye and the Barley, if both were malted, should just about have had enough enzymes between them to convert the dense maize mash to fermentable sugars but with an unchanged gravity reading something's wrong ???

AM 8)

Re: Stalling yeast

PostPosted: Tue Apr 30, 2013 11:47 am
by Distillingchris
no sorry, its 1.015 at the minute, meaning about a 4.5% wash as is