Autolysing Yeast

[Bidtfaun]

I did a search and nothing came up, so......

Does anyone know how long it takes before the yeast starts to autolyse, or eat itself?

I am guessing a cold 2ndary ferment would put them to sleep so they don't do this...but if you forgot to pay attention to it and let it go unracked for say a few more weeks than normal (with a 2-3 week primary) at primary temps...at what point would you have dead yeast?

 

[PhilS]

This is an interesting subject. I guess it depends on a number of factors.

The closest I found using Google was this link:-

http://www.draymans.com/Articles/Autolises.php

It gives a lot of information on the reasoning for this, but does not show a definite timeline. I guess that it is brewer specific to the conditions that you provide for the yeast and the environment they live & breed in.

Regards,
Phil

 

[Ziggy-san]

In my experience, the experience of my brewing friends, the collective experience of Tastbrew.com, bodensatz.com and the HBD, yeast autolysis is an extremely rare occurence.

I personally have left beer on the trub in the primary fermentor for six weeks and cider for two months with no adverse effects. Admittedly, the fermentation temperature for these particular brews varied between 55F and 60F (13C-15.5C) for then entire period they were exposed to the yeast cake, so it is feasible that higher temps might affect the autolysis process. However, you don't really want to go above 65F (excepting saisons and Bieres'dGarde) due to off-flavors ANYWAY...

From what I've read, yeast autolysis happens when the buggies burst due to a lack of nutrients or the presence of various stressors. If you pitch healthy yeast using yeast nutrient and aerate well, I don't see autolysis as a viable occurrence before the alcohol puts them down to sleep.

 

[Lufah]

I just know I've left ales on the yeast in primary for six weeks before without problems.

Travis