How long is too long to ferment?

[jceg316]

Due to a nasty fusel taste in a recent batch, I've been doing much research into what caused this and one issue is leaving the beer on the trub for too long.

I was wondering how long is too long though. As it appears with modern yeast beers can sit on the trub for long periods, and some say it helps to leave the beer on the trub as yeast will get rid of some off flavours. The idea of racking to secondary is actually a pretty old idea due to poorer quality yeasts.

Was hoping to spark up a discussion about this and get your opinions.

 

[clibit]

From the stuff I have read, 4 weeks in primary is about the max advisable. I'm sure you'd get away with longer in most cases, but not sure what the benefit would be. I'd be interested to know why modern yeast is different from old yeast. Have they caught up with the digital age? :-)

 

[MyQul]

The times I've had fusils are from a) fermenting too hot b) to much temperature swings which must have stressed the yeast despite not going above the yeast's recommended temp range

 

[clibit]

My understanding is that the risk of yeast autolysis starts at around 4 weeks. But there are differences of opinion out there. I usually bottle after between 2 and 3 weeks in primary. I wait for it to be clear, on the assumption that conditioning will take place in the bottle and any issues will be resolved in the bottle as it conditions. My second ever AG didn't clear well and I bottled it. It was a long time before it was good to drink, but it got there eventually. Last few bottles were great!

 

[nbpicklesno2]

I'm one of those who take it out of primary between seven and ten days, sometimes racked straight into the bottle. Depends on the beer and how the yeast has done its work.

 

[Twostage]

Shame it was a nasty taste. Was it butterscotchy ? I made one with that 'problem' and I actually liked it. As MyQul has said fusils are from too high temperature at the start of the ferment. Increasing the temp at the end actually helps the yeast to assimilate the nasty chemicals produced in the early stages.

As for how long, I'm in the camp that measures it in days rather than weeks so autolysis tends not to be a problem for me.

 

[HebridesRob]

I've never knowingly tasted "yeast bite" due to autolysis but the tastes are generally described as "meaty, rubbery, and sour". I do search but I can't find anything definitive on how long is "safe" to leave beer on the trub.The kind of thing you find says "no more than a week or autolysis and off flavours may occur" and "depends on vitality of the yeast when pitched". My latest bottled beer was left for four weeks and there's nothing that I can detect.

 

[jceg316]

Thanks for your replies. There's a thread on homebrew talk I found which discusses how yeàst is better now than it was 20 years ago but for the life of me I can't find it.

I think in this case the temperature fluctuations weren't good for the yeast as I don't have a way of properly controlling temps. I can stop the beer getting cold but can't cool it down. Alsonibwas using Abbaye which I think is very sensitive.

It didn't have a butterscotch or diacetyl taste. It tasted of fusel alcohols, like nail varnish remover or bad vodka.

 

[Twostage]

Thanks for your replies. There's a thread on homebrew talk I found which discusses how yeàst is better now than it was 20 years ago but for the life of me I can't find it.

I think in this case the temperature fluctuations weren't good for the yeast as I don't have a way of properly controlling temps. I can stop the beer getting cold but can't cool it down. Alsonibwas using Abbaye which I think is very sensitive.

It didn't have a butterscotch or diacetyl taste. It tasted of fusel alcohols, like nail varnish remover or bad vodka.

Hmmm. Doesn't sound nice does it ?

Sounds like you need a brew fridge 😉

 

[dweb]

I`ve got an Apollo Ipa in the fv for nearly 3 weeks now,mainly due to the fact that my 3 cornies still have grog in them.I should empty 1 tonight so will rack tomorrow evening.That`s the longest I`ve left 1 in the fv.so I hope it`s good.

 

[jceg316]

I DO need a brew fridge, but it's proving difficult to get my hands on a fridge and I'm definitely not good at DIY stuff.