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How long can a mash sit?

Posted: Sat Jan 21, 2012 4:28 pm
by Steep-n-Rocky
How long can a mash sit w/o being distilled? I have a bourbon mash which I cooked Jan. 8 which I have not stripped yet. I strain out the grain and meant to strip earlier but yada yada yada life got in the way. It now has a white film on top and a distinctly non-beer smell. In my research on the forum I did find an answer for a wash but not a mash. Believe me when I say I appreciate any and all advice.

Re: How long can a mash sit?

Posted: Sat Jan 21, 2012 4:35 pm
by beelah
Haven't done AG, but I am assuming that is what you have there. Did you pitch any yeast? Is it in a open container? Did you notice any fermentation taking place at all? I know that some folks here use natural ambient yeast to start their fermentation , but I am not sure what you have there? It does sound like it has spoiled but hard to tell. I am sure someone else will come along soon and let you know.

Re: How long can a mash sit?

Posted: Sat Jan 21, 2012 4:46 pm
by Steep-n-Rocky
Sorry I did not add any extra info Beelah. This AG mash is fully fermented and was ready to run quite some time ago, I just didn't get a chance to run it when I wanted to.

Re: How long can a mash sit?

Posted: Sat Jan 21, 2012 4:49 pm
by Dnderhead
yes sound infected,but run it anyway,,leaving a AG sit to long is not a good idea as you found out. it has not been sterilized as some others have,and grain can harbor bacteria.

Re: How long can a mash sit?

Posted: Sat Jan 21, 2012 7:59 pm
by Steep-n-Rocky
Thanks Dnderhead. I really appreciate your advice and will post how it turns out.

Re: How long can a mash sit?

Posted: Sun Jan 22, 2012 4:31 am
by rtalbigr
I get that white film on my AG washes sometimes after only a couple a days, to date it has never been a problem. If ya keep your carboys clean and capped, even when empty you'll reduce a lot of potential problems. I have often let my mashes set for up to three weeks before I can strip and, knock on wood, haven't had any problems.

Big R

Re: How long can a mash sit?

Posted: Sun Jan 22, 2012 7:14 am
by Yunus
Whats the ABV of the mash? You don't find many bacteria/bugs that will tolerate much above 6-8%. I mean if you leave it to the open air it will go bad but if you have it in a bucket or other semi sealed container with an airlock you should be fine for months. Beers have hops in them and that helps preserve the beer.

I have had mead (honey) sit for over a year with no issue at all.

Re: How long can a mash sit?

Posted: Sun Jan 22, 2012 5:40 pm
by Steep-n-Rocky
I'm running it right now so I should have some "experience" very soon.

Re: How long can a mash sit?

Posted: Sun Jan 22, 2012 6:56 pm
by King Of Hearts
It could be some bug but dont worry, all your sugar was eatin some time ago.

Re: How long can a mash sit?

Posted: Sun Jan 22, 2012 8:14 pm
by Steep-n-Rocky
The verdict is in and the outcome was less than impressive. I ran this as a stripping run and the alcohol has a distinct "thinner" flavor. Both the volume and ABV were less than expected as well. I will not add this to the bourbon cache being saved for a spirit run. I'm not sure what to do with it but I'm not going to drink it. Lesson of the day: don't let the wash sit too long (weeks) if you can help it.

Re: How long can a mash sit?

Posted: Mon Jan 23, 2012 5:00 am
by Junkaboy
I had a similar "problem" on my last run
But since all my fermenters sit inside a fridge with a temp controller, when it was ready and I noticed I couldn't run it for the next 15 days, I set the temp to 36F and let it sit there.

Re: How long can a mash sit?

Posted: Mon Jan 23, 2012 6:43 am
by King Of Hearts
Steep-n-Rocky wrote:How long can a mash sit w/o being distilled? I have a bourbon mash which I cooked Jan. 8 which I have not stripped yet. I strain out the grain and meant to strip earlier but yada yada yada life got in the way. It now has a white film on top and a distinctly non-beer smell. In my research on the forum I did find an answer for a wash but not a mash. Believe me when I say I appreciate any and all advice.
What yeast did you use and what % abv. Yeasts can consume alcohol but not that much.

Re: How long can a mash sit?

Posted: Mon Jan 23, 2012 7:22 am
by Dnderhead
"Yeasts can consume alcohol but not that much."
yeast wont "consume" alcohol ,alcohol is toxic to yeast.thats why you have off flavors,stalled ferments with hi ABV wash/mashes.

Re: How long can a mash sit?

Posted: Mon Jan 23, 2012 7:32 am
by Steep-n-Rocky
The ABV of the wash was 8.5 - 9 and the yeast was washed from a previous bourbon mash. This was not a persistent problem with the mash as it was very good up until about 4-5 days ago when it turned. I believe it was an infection but what type I do not know. Again, my lesson was not to let wash sit longer than it needs to if possible.

Re: How long can a mash sit?

Posted: Mon Jan 23, 2012 7:40 am
by King Of Hearts
Dnderhead wrote:"Yeasts can consume alcohol but not that much."
yeast wont "consume" alcohol ,alcohol is toxic to yeast.thats why you have off flavors,stalled ferments with hi ABV wash/mashes.
It's toxic to humans too, but we consume it. See yeast and bacteria. http://en.wikipedia.org/wiki/Alcohol_dehydrogenase" onclick="window.open(this.href);return false;" rel="nofollow

In high sugar washes above 10% abv if not enough yeast or nutrients are added they will poop out and stop eating, not all of them die from alcohol poisoning.

Re: How long can a mash sit?

Posted: Mon Jan 23, 2012 7:43 am
by King Of Hearts
Steep-n-Rocky wrote:The ABV of the wash was 8.5 - 9 and the yeast was washed from a previous bourbon mash. This was not a persistent problem with the mash as it was very good up until about 4-5 days ago when it turned. I believe it was an infection but what type I do not know. Again, my lesson was not to let wash sit longer than it needs to if possible.
what yeast? Did you notice any green apple aroma? How many gererations was it? Did it check below 1.000 with the hydrometer?

Re: How long can a mash sit?

Posted: Mon Jan 23, 2012 11:39 am
by Steep-n-Rocky
The yeast was T-58 about 3-4 generations old, the hydrometer was above 1.00 and it actually had a faint banana mixed with thinner. It carried over in the heads very strongly and not so much in the middle or toward the end. However, not knowing what it is I am trying to think of a new purpose for the distillate.

Re: How long can a mash sit?

Posted: Mon Jan 23, 2012 11:56 am
by King Of Hearts
Steep-n-Rocky wrote:The yeast was T-58 about 3-4 generations old, the hydrometer was above 1.00 and it actually had a faint banana mixed with thinner. It carried over in the heads very strongly and not so much in the middle or toward the end. However, not knowing what it is I am trying to think of a new purpose for the distillate.
T58 is a Belgian yeast strain. I used it before to make a Belgian Dubble. Came out pretty good. I wouldn't use it for whiskey tho. Might try it once to see how it came out. It has a lot of different esters like that bananna or isoamyl acetate. The wash could of ran out of nutrients causing an incomplete fermentation. The previous 3 batches must have been good or you wouldn't have made a fourth.

Re: How long can a mash sit?

Posted: Mon Jan 23, 2012 1:32 pm
by Steep-n-Rocky
It was an experiment and I did like the t-58 "peppery" flavor (can't think of a better way to describe it). On that note, I have never used Whiskey Yeast (dry) with AG but am considering it as my neighbor does and the flavor, same grain bill I use, is pretty good. I've used Nottingham and ec-1118 and ready to try a new yeast for bourbon.

Re: How long can a mash sit?

Posted: Mon Jan 23, 2012 1:44 pm
by King Of Hearts
Steep-n-Rocky wrote:It was an experiment and I did like the t-58 "peppery" flavor (can't think of a better way to describe it). On that note, I have never used Whiskey Yeast (dry) with AG but am considering it as my neighbor does and the flavor, same grain bill I use, is pretty good. I've used Nottingham and ec-1118 and ready to try a new yeast for bourbon.
I used Safale 04 British Ale the batch before last with 60% flaked corn, 20% Canadian Wheat Malt and 20% distillers malt. Started @ 95 degrees. It had a light blueberry aroma. Ran it twice and added 1 stick of medium toast and charred oak. It has a butterscotch aroma and flavor, I'm adding more oak.

Last batch same bill I used Red Star fresh cake yeast. It had a fruity aroma, draining off the grain now.