Stuck Bourbon Ferment

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werkkrew
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Stuck Bourbon Ferment

Post by werkkrew »

Hi All -

I have a fermentation that I believe is stuck - or at least moving along much slower than I am used to.

I made a recipe I have made many times before - it's a wheated bourbon.

10 gallons water
20 lbs cracked corn (milled relatively fine)
5 lbs malted wheat
2 lbs 6-row

Added some gypsum and brought the water to a boil, added the corn, let the corn sit at about 195F for about 90 minutes until it was as thick as oatmeal. Added SebStar HTL to thin it out and let it get to about 150 naturally. Added my wheat/barley, held for about 60 minutes with the addition of some SebAmyl GL for insurance. Added some backset until the pH was about 4.5, batch sparged the mash through a laundry bag.

Ended up with about 11 gallons of wort with a SG of 1.060 and a ph of 4.5. Used a wort chiller to get the temp down to about 75F and pitched two 11.5g packets of safale US-05 ale yeast directly onto the wort.

Generally speaking this recipe/process has worked out great for me in the past, I've done it several times. After about 7 days it ferments out totally dry to 1.000 or 0.998 even.

Yesterday SG was 1.030.
Today is day 7 and its only down to 1.027 according to both my hydrometer and refractometer. So it is moving down but the activity is extremely slow and the airlock isn't even bubbling.

Temperature is held at a stable 73F in my basement using a temperature controller.

Tested the pH tonight and its 3.35

My gut tells me the pH is too low but I never tested the pH of this recipe before so for all I know it could be perfectly normal. Is there anything I might have around the house or have easy access to at the grocery store I could use to safely raise it a bit?

Any other ideas on how I can salvage this? Perhaps I can just wait it out and it'll get there eventually?

I've had a couple other batches ferment out really poorly before and I wasn't able to do anything about it other than distill what little alcohol I managed to produce and it feels bad to waste so much time / money / energy to get essentially nothing out of it at the end.
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Re: Stuck Bourbon Ferment

Post by Stonecutter »

Addressing PH levels alone. You can always add some oyster/coral shell like one would with a sugar wash. About a cup worth. I’m not sure where you reside but local farming supplies or Amazon always stay stocked with the oyster. I’m not too sure that there PH level is the main culprit though :problem:
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Re: Stuck Bourbon Ferment

Post by still_stirrin »

Let it alone. The gravity is still falling. You can’t judge progress by the airlock. You could try to warm it a little, like moving the fermenter to a room that is warmer. That might help speed up attenuation. Otherwise, just wait it out.
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p.s. - a pH 3.5 is low. If you want to raise it, use a tablespoon or 2 of rehydrated calcium hydroxide (pickling lime), which can be found in the pickling aisle of your grocery store. Rehydrate the powder with a cup of warm water and gently mix it back into your fermenter.
Last edited by still_stirrin on Thu Aug 04, 2022 7:02 pm, edited 1 time in total.
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Re: Stuck Bourbon Ferment

Post by bunny »

werkkrew wrote: Thu Aug 04, 2022 5:46 pm Hi All -

I have a fermentation that I believe is stuck - or at least moving along much slower than I am used to.

I made a recipe I have made many times before - it's a wheated bourbon.

10 gallons water
20 lbs cracked corn (milled relatively fine)
5 lbs malted wheat
2 lbs 6-row

Added some gypsum and brought the water to a boil, added the corn, let the corn sit at about 195F for about 90 minutes until it was as thick as oatmeal. Added SebStar HTL to thin it out and let it get to about 150 naturally. Added my wheat/barley, held for about 60 minutes with the addition of some SebAmyl GL for insurance. Added some backset until the pH was about 4.5, batch sparged the mash through a laundry bag.

Ended up with about 11 gallons of wort with a SG of 1.060 and a ph of 4.5. Used a wort chiller to get the temp down to about 75F and pitched two 11.5g packets of safale US-05 ale yeast directly onto the wort.

Generally speaking this recipe/process has worked out great for me in the past, I've done it several times. After about 7 days it ferments out totally dry to 1.000 or 0.998 even.

Yesterday SG was 1.030.
Today is day 7 and its only down to 1.027 according to both my hydrometer and refractometer. So it is moving down but the activity is extremely slow and the airlock isn't even bubbling.

Temperature is held at a stable 73F in my basement using a temperature controller.

Tested the pH tonight and its 3.35

My gut tells me the pH is too low but I never tested the pH of this recipe before so for all I know it could be perfectly normal. Is there anything I might have around the house or have easy access to at the grocery store I could use to safely raise it a bit?

Any other ideas on how I can salvage this? Perhaps I can just wait it out and it'll get there eventually?

I've had a couple other batches ferment out really poorly before and I wasn't able to do anything about it other than distill what little alcohol I managed to produce and it feels bad to waste so much time / money / energy to get essentially nothing out of it at the end.
Kirkland ultra strength antacid have 1000mg of Calcium Carbonate. Crush 5 or 6 and throw them in. Check pH in an hour.
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Re: Stuck Bourbon Ferment

Post by werkkrew »

I have some Calcium Chloride for my salt water aquarium on hand, anything else I'd have to go shopping and wait until tomorrow.
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Re: Stuck Bourbon Ferment

Post by still_stirrin »

werkkrew wrote: Thu Aug 04, 2022 7:03 pm I have some Calcium Chloride for my salt water aquarium on hand, anything else I'd have to go shopping and wait until tomorrow.
No, that’s a salt. It is NOT what you need to raise the pH.

Get this:
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Re: Stuck Bourbon Ferment

Post by werkkrew »

Okay I will get some tomorrow AM, how much should I add?

Are you fairly confident pH is the issue here, will I need to add more yeast?
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Re: Stuck Bourbon Ferment

Post by still_stirrin »

werkkrew wrote: Thu Aug 04, 2022 7:13 pm Okay I will get some tomorrow AM, how much should I add?
I answered this already.
werkkrew wrote: Thu Aug 04, 2022 7:13 pm Are you fairly confident pH is the issue here, will I need to add more yeast?
With a measured pH 3.35, the yeast will tend to go dormant (the H ions slow/stop yeast metabolism). They likely won’t die, just fall down to the bottom of your fermenter. Raising the pH, even slightly will help. If you can raise it back to 4.0 or 4.2, then you’ll see activity start again.

Next time you do this wash/mash, add some calcium carbonate in the form of oyster shell or chicken scratch or even a chunk of marble to the fermenter and it will buffer the acid production (which is a step in the fermentation process).
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Re: Stuck Bourbon Ferment

Post by Twisted Brick »

still_stirrin wrote: Thu Aug 04, 2022 6:53 pm
p.s. - a pH 3.5 is low.
Backset harvested over successive generations can grow acidic. If this is the case, use fresh backset or just use less of it.
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Re: Stuck Bourbon Ferment

Post by NZChris »

I don't use numbers off the net because every wash is different. If correcting pH, I use small additions of slaked lime, checking the pH before each addition and keeping notes for next time. When I reach an ok range, I then put in whole shells to hold it there.
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Re: Stuck Bourbon Ferment

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werkkrew wrote: Thu Aug 04, 2022 5:46 pm
Added some gypsum and brought the water to a boil, added the corn, let the corn sit at about 195F for about 90 minutes until it was as thick as oatmeal. Added SebStar HTL to thin it out and let it get to about 150 naturally. Added my wheat/barley, held for about 60 minutes with the addition of some SebAmyl GL for insurance. Added some backset until the pH was about 4.5, batch sparged the mash through a laundry bag.
As you sparge pH should rise, the last of your runnings (not the overall mash) should end up somewhere between 5.8 and 6.0. Looking at your grain bill vs output you may have under sparged a little bit. Your starting pH was a little low, should have been above 5 before the backset addition. When was the last time you calibrated your pH meter? I wouldn't add anything until the yeast actually stops.

You said you added gypsum at the beginning of the mash, have you gotten a water analysis, or what made you decide on this?

Refractometer is no longer accurate after fermentation begins.

Recipe looks pretty good.
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Re: Stuck Bourbon Ferment

Post by werkkrew »

Ben wrote: Fri Aug 05, 2022 5:53 am You said you added gypsum at the beginning of the mash, have you gotten a water analysis, or what made you decide on this?
It's funny you ask because I was just asking myself that very question. The only answer I have is that I think when I was researching corn heavy recipes almost everyone adds gypsum so I figured it can't hurt...I don't actually have a good reason why other than that...

Ben wrote: Fri Aug 05, 2022 5:53 am Refractometer is no longer accurate after fermentation begins.
Ah that's true. It's been a couple years since I did this so I had completely forgotten about that fact, although so far it lines up pretty closely with the hydrometer.
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Re: Stuck Bourbon Ferment

Post by greggn »

werkkrew wrote: Thu Aug 04, 2022 5:46 pm
pitched two 11.5g packets of safale US-05 ale yeast directly onto the wort.

Moving past the pH discussion ...

I'm curious why you don't rehydrate/proof your yeast before pitching ? I realize it's not *necessary" to do so but it's an easy means of roughly determining yeast viability.
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Re: Stuck Bourbon Ferment

Post by shadylane »

werkkrew wrote: Thu Aug 04, 2022 5:46 pm Hi All -

I have a fermentation that I believe is stuck - or at least moving along much slower than I am used to.

I made a recipe I have made many times before - it's a wheated bourbon.
I figure it's not stalled, instead the yeast is done eating the fermentables.
The last time it happened to me, was when I got the htl and gluco mixed up . :oops:
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Re: Stuck Bourbon Ferment

Post by werkkrew »

Just as an update - I corrected the ph to about 4.2 using pickling lime and fermentation picked back up. As of today it got to 1.000 so I'm calling it a success.

No idea if it would have continued without intervention but I believe the ph correction helped.
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Re: Stuck Bourbon Ferment

Post by Twisted Brick »

Great! Another lesson learned. From this thread you may have discovered that one doesn't just adjust one's pH (in this case with gypsum) just because another member did it. Every distiller's water chemistry is different and needs to be adjusted accordingly. It's helpful to start with a water analysis from your city. Beer forums are great for learning how to adjust water. The fewer additions you make to your ferment the better, IMO.

Suspending a small paint strainer bag of oyster shells (I use sea shells from the beach) is cheap insurance.

Yeast are wonderful little beasts, but are fragile and lack the ability to discriminate between solutions they are dropped into. Pitched dry directly into a fresh wash can kill up to 50% of them. By getting into the habit of making a starter, (same grain bill as the mash, only lighter in gravity) one can 'condition' ones yeast as well as build up the cell count. This means you can start with a partial pack of yeast (I start with 4g) instead of pitching 2 packs, thus saving more than a few bucks if you're mashing more frequently. More importantly, starters can help dial in the consistency of your ferments.
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Re: Stuck Bourbon Ferment

Post by still_stirrin »

Twisted Brick wrote: Wed Aug 10, 2022 5:41 pm… one doesn't just adjust one's pH (in this case with gypsum) just because another member did it…
FYI: Gypsum (calcium sulfate) adds permanent hardness (calcium ions) to brewing water; 1 gram per gallon adds 62 ppm calcium, 147 ppm sulfate. Brewers that use distilled, or RO, water like to add some gypsum back into the water to give it some hardness. Gypsum can also be used to lower the pH of water.

Also note that gypsum can be a source of sulfur in your ferment. This may pose a problem for your products offstill.
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Re: Stuck Bourbon Ferment

Post by Mr Sippy »

Gypsum does NOT lower pH. Adds calcium sure but doesn't remove H ions

edit meant to say adds sulfate
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Re: Stuck Bourbon Ferment

Post by Ben »

Mr Sippy wrote: Fri Aug 12, 2022 2:43 am Gypsum does NOT lower pH. Adds calcium sure but doesn't remove H ions

edit meant to say adds sulfate
I think you should do some basic research on mash pH and the effect of gypsum. Then come back and tell us how and why gypsum doesn't work.
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Re: Stuck Bourbon Ferment

Post by Mr Sippy »

I just did. I wrote in error of context of simple water and soil chemistry not considering secondary/additional reaction. Not a brown liquor guy. Mea culpa. Apologies to OP for the distraction.
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