Restarting stuck ferment

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regfixit
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Restarting stuck ferment

Post by regfixit »

I'm making my first sugar wash for a neutral and it seems to have stopped fermenting at 1.050 SG after 9 days.
I'm using 6Kg of white sugar made up to 25 L and pitched Youngs Dried Active Yeast, which was hydrated first and it came to life, and also added some yeast nutrient. OG was 1.100 and temperature 21C.
Fermentation has started but seems now to have stopped with an ABV of around 6.5%.
SG.JPG
I am wondering whether to try to restart it with some Turbo yeast (which I've read on here is to be avoided at all costs), or to try some EC-1118 or is it just a bad job ? Could I distill what I have with the sugar left in or will that mess up my boiler/still ?

Grateful for any tips.
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NZChris
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Re: Restarting stuck ferment

Post by NZChris »

What is the pH?
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Saltbush Bill
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Re: Restarting stuck ferment

Post by Saltbush Bill »

If Youngs Dried Active Yeast,is a bakers yeast thats kind of cool for it.....try bumping the temp up to around 33-34C
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Re: Restarting stuck ferment

Post by Toxxyc »

It's probably the pH. Get a base and dump it in, little by little, to see if it helps. I had a stuck ferment a while ago and dumped in half a teaspoon of KOH (potassium hydroxide) and two days later it was done. I don't have a pH meter though and I am NOT the most experienced, but I know that sugar washes can get really acidic, really fast.
regfixit
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Re: Restarting stuck ferment

Post by regfixit »

Thanks for quick replies. The yeast is a wine and beer making yeast.

I'm not at home at the moment but after doing some more reading I am indeed thinking about the ph @NZChris and @Toxxyc. I didn't add any citric acid. My water is very soft and I think ph is probably 7 or more.

I'm back on Sunday so will check the ph and if it's high will lower it and add some more yeast and see how it goes.
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shadylane
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Re: Restarting stuck ferment

Post by shadylane »

A sugar wash with a starting gravity of 1.100 that stalls @ 1.050 isn't likely to restart.
Ya might adjust the pH and pitch some EC1118. That might get it going again for a little more.
But even then the distillate won't taste very good.

As they say an ounce of prevention is worth a pound of cure.
Next time only use enough sugar for a starting gravity of around 1.070 :wink:
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Re: Restarting stuck ferment

Post by shadylane »

regfixit wrote: Fri May 14, 2021 12:44 am
I'm back on Sunday so will check the ph and if it's high will lower it and add some more yeast and see how it goes.
Ya got it backwards brother :lol:
Acidic is a # lower than 7 and base is higher than 7
It's probably too late now but what the ferment needed was to have the pH around 4 or 5ish
The ferment started around 7 and quickly drops as the yeast gets going.
In other words Ya don't need to lower the pH, nature is doing that more than needed. :wink:
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Re: Restarting stuck ferment

Post by regfixit »

I've just read this about the yeast I used
"Standard form of yeast used for brewing, can be used for beer or wine but more suited to beer and low alcohol wines."

So I think it might still be worth a salvage with new yeast, higher temp and adjust the ph if needed.....
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8Ball
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Re: Restarting stuck ferment

Post by 8Ball »

shadylane wrote: Fri May 14, 2021 12:55 am A sugar wash with a starting gravity of 1.100 that stalls @ 1.050 isn't likely to restart.
Ya might adjust the pH and pitch some EC1118. That might get it going again for a little more.
But even then the distillate won't taste very good.

As they say an ounce of prevention is worth a pound of cure.
Next time only use enough sugar for a starting gravity of around 1.070 :wink:
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Re: Restarting stuck ferment

Post by v-child »

Is the cost of 6kg and a bit of cheap yeast worth all the trouble and time? Run it as is, learn the lessons and try again.
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Re: Restarting stuck ferment

Post by StillerBoy »

v-child wrote: Fri May 14, 2021 6:16 am Is the cost of 6kg and a bit of cheap yeast worth all the trouble and time? Run it as is, learn the lessons and try again.
In agreement..

Your process, recipe and your lack of properly informing how a sugar wash is done, is your issue..

Best to start over, than spending time and resources leading nowhere.. that wash will never finish anywhere near dry for many reason some outline and some not..

You have many issues.. some are related to ingredients, temperature both at pitching and during, Ph both at start and during, and the yeast..

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Re: Restarting stuck ferment

Post by Deplorable »

Sound advice here.
Run it, and learn the rest of the lesson hidden in the quality of the product it makes.
Then, make another wash using a Tried and True recipe like Shady's Sugar Shine and compare the two finished products. Then you'll understand what you did wrong and the impact it has at the end.
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Re: Restarting stuck ferment

Post by contrahead »

regfixit wrote: Fri May 14, 2021 12:21 am
Fermentation has started but seems now to have stopped with an ABV of around 6.5%.
What's the alcohol tolerance of your yeast? Some yeast companies don't publish the info but many do. A 6.5% ABV would be considered adequate and acceptable for some bread and ale yeast. That's about as high an ABV as they can ever produce. Alternatively you'd expect a typical red wine yeast to tolerate about twice that level of ethanol, before it stops working.

(The posted ABV tolerances that I briefly searched for a few minutes ago – seem to be bumped a percentage point or two from what they were a few years ago). Here is a current mix of figures, from five different wine yeast sellers.
https://winemakermag.com/resource/yeast-strains-chart
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Re: Restarting stuck ferment

Post by StillerBoy »

contrahead wrote: Fri May 14, 2021 1:00 pm What's the alcohol tolerance of your yeast?
I think he's making reference to the level indicated on the hydrometer reading at the level it's stalled..

But the issue has nothing to do with the present level of the abv in the wash or the yeast used.. the wash has a issue with either the temp fermented at, the Ph its at, or way to much sugar at start, or maybe all three combine..

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Re: Restarting stuck ferment

Post by contrahead »

StillerBoy wrote: Fri May 14, 2021 3:08 pm I think he's making reference to the level indicated on the hydrometer reading at the level it's stalled..
Perhaps. However :
He says he started with an OG of 1.10 and after 9 days had a SG of 1.050 (which indicates fermentation has been taking place). If [ABV = (OG - FG) x 131] as explained on this page - Using a Mash Hydrodrometer then he gets (.050 x 131) or 6.55% ; just like the text says.

I think it's entirely possible that he saw his OG setting at 1.10 in the beginning, looked at this chart; and then consequently expected to get 13% ABV. A rookie not yet experienced enough to detect the presence of alcohol in his wash – by the smell test. I think it entirely possible that after 9 days he is sitting on 6.55% ABV and expected too much for that particular yeast; and possible that his problem has absolutely nothing to do with pH or temperature.
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Saltbush Bill
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Re: Restarting stuck ferment

Post by Saltbush Bill »

contrahead wrote: Fri May 14, 2021 1:00 pm A 6.5% ABV would be considered adequate and acceptable for some bread and ale yeast.
contrahead wrote: Fri May 14, 2021 1:00 pm That's about as high an ABV as they can ever produce.
A quick look around the net will see figures for bread yeast of 6% right through to 14% and beyond. Personally I'm sure it can do at least 12% ABV quite happily, and if it really had to 15%+.
Not recommending anyone use it that way........but it is incorrect to say that its limit is 6.5% IMO.
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Re: Restarting stuck ferment

Post by regfixit »

Thanks for all the comments and advice. A few replies comments in general:
The wash was 6kg of sugar made up to 25 litres and based on the calculator I used I was expecting around SG 1.09 and an overall ABV of 14%. As I've made quite a lot of wine to that level with no issues, I didn't think I was being "greedy" at that level and I'd read all the warning on here about trying to use turbo yeast and get 20+ % brews so was not trying to get to that level.

I'd read the Birdwatchers recipe which uses 18kg made up to 80 litres so that would equate to 6Kg made up to 26.7 litres so I don't think my wash was over ambitious to be saying 6 kg made up to 25. I didn't fancy the tomato paste on my fementer equipment so I used Yeast nutrient instead. I hadn't seen Wineos plain sugar wash with the additional gypsum and epsom salts or Shady's sugar shine using Oyster shells to help control acidity.

I've just got back home and Ph is 3.1 so I think my issues were:
1) I have very soft water so no alkalinity to control the acidity.
2) The yeast I used, although it states general purpose wine and bear yeast, actually seems more like a low alcohol wine or beer yeast
3) Perhaps a bit too much sugar, although with some alkalinity and a better yeast might have been OK

The reason for asking for advice on here how to restart it, was not really for the cost but the time involved. I work alternate weeks away from home so was hoping to get it going again at least down to say 1.02 this week, rather than start from scratch.

Anyway, it's all learning experience and thanks for the input and advice to all
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Re: Restarting stuck ferment

Post by rubberduck71 »

+1 to the good advice above.

3.1 pH will definitely stall yeast. I had a tequila wash (agave syrup + sugar) stall out under similar circumstances. You could split the 26L wash by pouring half in another bucket, topping up with water (which will raise the pH), & add a small coffee mug sized bag of crushed oyster shells. A 5lb bag is ~$5 USD at you local grain/feed store. Hop bags are ~$0.25 USD each, so buy a couple to have on hand.

When the wash is done fermenting, you can salvage the bag from the trub on the bottom. Just wash it out for next time.

Oyster shells are cruise control for your pH. When it approaches too low a threshold, the acidity starts breaking down the calcium in the shells, which brings up the pH to a more friendly range for our yeastie friends. Then it automatically stops breaking down as the pH rises.

Search up "stalled wash" in the blue tool bar at the top of this page. You'll see a ton of similar info.

Good luck!

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Re: Restarting stuck ferment

Post by contrahead »

Saltbush Bill wrote: Sat May 15, 2021 11:04 pm Personally I'm sure it can do at least 12% ABV quite happily, and if it really had to 15%+.

........but it is incorrect to say that its limit is 6.5% IMO.
I think your optimistic. But you do have a point. In a way what you are saying is similar to stating that Campden tablets or sodium benzoate - do not kill yeast. (Technically these only stun yeast; sometimes abruptly, but if removed from the preservative's influence the dormant yeasts might recover). For all “intents and purposes” though, the yeasts obviously stop working so it seems like they're dead.

Alcohol tolerance is a notion sometimes too focused upon specific yeast type rather than to all the important little accompanying factors involved when baking, brewing or distilling. Substrate concentration, carbohydrate level, wort nutrition, osmotic pressure/water activity and temperature are all critical to yeast performance. These factors must be considered before determining “tolerance”.

Nonetheless the notion that ABV tolerances differ by yeast strain still holds; the differences still obvious. For centuries bakers have been unknowingly selecting yeast that were optimized for making gas bubbles (rather than ethanol) which could then be entrapped by the gluten in moist flour – to make bread rise. Likewise champagne makers like the Benedictine monk Dom Pérignon, were inadvertently practicing artificial selection as they isolated some of the highest attenuating and highest ethanol tolerant yeast types we have. (To make the sparkling wine called Champagne in the old days; in winter they'd bottle it and then freeze the bottles upside down. Later they'd un-cork the bottles and let the sediments be pushed out before replacing the corks and wiring those back down. Secondary fermentation by those tolerant yet voracious yeast strains created trapped gas; very strong bottles were required to hold it in).

Here are two external links for more information on the topic of alcohol yeast tolerance. Presumably there is an authentic impetus for locating or developing a low-tolerance wine yeast. This link talks a little about genetic modification and about using salt in the growth medium to cause osmotic stress (which produces more glycerol and therefore less alcohol).

This second link uses more scientific language that is unapologetically obscure, but it focuses more directly upon the topic of ethanol tolerance.
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regfixit
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Re: Restarting stuck ferment

Post by regfixit »

I put a few teaspoons of sodium bicarbonate in ( I only had that in my cupboard not calcium bicarbonate ) last night and some EC-1118 yeast and it's now bubbling away merrily. pH 4.5 and SG is now 1.025 so looks like it might be OK. My still is new so I can use this as a sac run anyway.

I'm going to the fish shop tomorrow to get a dozen oysters as a treat and to put the shells in my next washes :)
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