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Slow fermentation and dead yeast Q

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pip

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I know there must have been lots of threads on this topic over the journey but i can't find one to post this question on, apologies if thats the case.

Well, the weather in my city has taken a cold autumnal turn. 27C(80F) average last week, this week we're down to 12-14C(58F). My brewing room is sitting at around 18C(66F) atm. The batches i have in the primaries (a blueberry and a mango) seem to have gone to sleep. No feeding at all for the last 24-36 hours - one is sitting at 1.07 and the other at 1.05. My only way of warming them is to immerse the buckets in hot water and stir until the must rises to 24C - ish (78F).

I'm worried that the temperature changes may damage the yeasties. Any thoughts? I'm using ec-1118.

Also, would it be correct to think that if a must returns the same sg reading 3 days in a row the yeast is dead (with high sugar content still in the must) and that it would be time to re-pitch some fresh yeast?
 

Johnd

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I know there must have been lots of threads on this topic over the journey but i can't find one to post this question on, apologies if thats the case.

Well, the weather in my city has taken a cold autumnal turn. 27C(80F) average last week, this week we're down to 12-14C(58F). My brewing room is sitting at around 18C(66F) atm. The batches i have in the primaries (a blueberry and a mango) seem to have gone to sleep. No feeding at all for the last 24-36 hours - one is sitting at 1.07 and the other at 1.05. My only way of warming them is to immerse the buckets in hot water and stir until the must rises to 24C - ish (78F).

I'm worried that the temperature changes may damage the yeasties. Any thoughts? I'm using ec-1118.

Also, would it be correct to think that if a must returns the same sg reading 3 days in a row the yeast is dead (with high sugar content still in the must) and that it would be time to re-pitch some fresh yeast?
Slow temp changes won't kill the yeast, so no worries there. Your yeast is probably just fine, but quite inactive due to the lower temps, get it into the mid 70's and keep it there and all should be well.
 

pip

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I know this already John, i dont know why i doubt myself or the process, but i sure am glad i have somewhere to go to be reassured and your posts read of experience and knowledge and from what i've read, they're gold (and a few others beside Johnd too). So thank you.

As a related aside, how many times can you pitch yeast in a batch before you give up or spoil the wine with too much yeast, hypothetically? I mean, there must be a point where a batch in the primary, for whatever reason, just wont ferment down. Have you ever had that? At what point do you say, something's wrong here this aint working and down the sink it sadly goes?

Come to think of it, is there a failure thread on the forum? That might be quite instructive.
 

Johnd

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As a related aside, how many times can you pitch yeast in a batch before you give up or spoil the wine with too much yeast, hypothetically? I mean, there must be a point where a batch in the primary, for whatever reason, just wont ferment down. Have you ever had that? At what point do you say, something's wrong here this aint working and down the sink it sadly goes?
I've never had to pitch a second yeast, as I've always had the parameters in line prior to pitching, and always use unexpired yeast, so I don't have a lot of experience with that. I believe that you can pitch yeast until the juice spoils, but if you've pitched a time or two with no results, continuing to pitch yeast is insane. Check parameters, adjust the ones that are wrong, and yeast will multiply and convert alcohol, it's what wine yeast does.....when conditions are favorable.
 

salcoco

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before pitching a second yeast there are many remedies that should be tried first. Temperature control is discussed, adding yeast nutrient, stirring the must are two others. some times to high an acid must will cause fermentation problems.
 

NorCal

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Yeast are like Zombies; you think they are dead, then given the right conditions, they come back to life. That is why is essential to ferment dry; eliminating the food source.
 

Noontime

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Love the zombie analogy! Like it's been said, if there is sugar and good conditions, the yeast will start chewing away. The yeast don't really die (the colony I mean, individual yeast cells do die), but just go dormant. Bring the temp up into the 60's and give it a good stir, and I bet it comes back. EC-1118 is pretty robust.
 

pip

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Yep, i stir the must morning and evening and i've adjusted the temperature, found a warmer spot in the house, (which ironically is the coolest spot in the summer). Sure enough the sg dropped last night but not by a whole lot. I bought 5 packets of ec-1118 last time i was at the brewing shop and i've just checked the use by day. 04-2017! Dang! What a rooky mistake that is, not checking the use by date. Still they seem to be working so should be fine.
 

pip

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Sorry to bump this thread. My small experimental batch of blueberry has stalled at 1.030.(3 days in a row) Been in the primary for 16 days. I've been reading a lot about the problems with straight blueberry wine and i wish i had read about this before i started! Lol...typical.

Anyhow, i'm thinking now of adding some yeast energizer and trying to lower the acid level with bicarbonate. I dont like sweet wine so i'm not really keen on getting it under airlock and risk producing an overly sweet drink.

Another concern is a very strong alcohol smell. It started at 1.095 so the abv is probably around 7-8% however the must smells like straight vodka or some kind of clinical alcohol. Could this indicate a high level of methanol?
 

stickman

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Possibly ethyl acetate, nail polish smell, in small amounts it can exaggerate the perception alcohol, it is often caused by wild yeast or bacteria, especially when fermentation conditions are not optimum.
 

pip

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Possibly ethyl acetate, nail polish smell, in small amounts it can exaggerate the perception alcohol, it is often caused by wild yeast or bacteria, especially when fermentation conditions are not optimum.
Hmm...not exactly like nail polish but ethyl acetate could be the problem, which would be very unfortunate although given i pitched out of date yeast, quite possible. Not easy to fix without ruining the wine, or so i've read. Anyway, i'll add nutrient, bicarbonate and see what happens.
 

Floandgary

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I have a 2017 Chilean bucket of Viognier which I started nearly 14 days ago. EC-1118 and some Fermax nutrient. No heater but daily stir have gotten down to 1.003. Been a little cooler (mid-upper 50's) for the past couple of days, and forecasts are keeping it there so things have really slowed. May just put the heater on the bucket for that last few .010 sg.!! Don't mind the slow ferment, actually desirable for the whites, but don't want it to sit inactive for too long. Had a Malbec along side with a heater on for the entire ferment (@11 days) and it is now happily dry in a carboy awaiting the next step...
 
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