Yeast Culture

[lokpikn]

Im doing some yeast cultues have done 3 different ones so far using white labs and dme im pitching the yeast at 24 degs. Ive got to problems doing this it starts to fement within 24 to 48 hrs my question is what temp do i want to leave it at after pitching lets say its a pilsner yeast which wants to fement at 13 degs is that the temp i want to culture at ???

 

[Weizguy]

IMHO, you want to culture the yeast at the temp you expect it to work, in your brew.
In that way, if there are any cells which excel at that temp, they will be the ones that will propagate and dominate the culture.

Ideally the yeast cells are all clones of the ideal culture (with no mutants) and will all work at the right temp. However, if you have a rogue/ mutant cell that works better at 24C, it will become the dominant type in your yeast culture and may (very likely) change the yeast characters, such as optimum ferment temp and flavour profile.

Having said that, I'm not aware how common it is to see mutation in yeast cultures, but it's reported to be quite common in W2308 (Munich lager).

Have I answered the question? :blink:

Best to culture at close to the temp range for the yeast.

Seth

 

[lokpikn]

Thanks Weizguy
That does answer the question. Ive done a culture of a pilsner white labs wlp 802 which likes it around 13 degs but i left it at room temp to fement which is around 20 degs. it has worked quite welll but when i pitched it into my wort after a few days it gave off a strong odour a bit like eggs (only a bit) i think that was my problem that i cultured at 20 degs pitced at 24 degs and fermented at 14 degs i think the yeast may be a bit confused.

 

[pint of lager]

Weizguy has covered most of the ground. If making a starter and pitching all the starter, run the starter at the correct temperature for the yeast.

When you pitch a litre of ale yeast starter into 20 litres, this represents 5% of the flavour of the beer, and if the yeast starter has been running too hot, this will contribute a component of unwanted fruityness to the end beer. With lagers, which you pitch a 2 litre starter, this represents an even greater unwanted flavour component.

Some people advocate making a decent sized starter at a higher temp, letting it ferment out, tipping the unwanted beer off and only pitching the yeast in about 100mls of starter beer.

If you progress to ag, a starter made from malt extract will contribute malt extract flavours to the wort.