Lager Yeast Starter

[edddy57]

I have been making yeast starters from some slants. Most recent is a Wyeast Danish. I'm told that you need a big starter ? around 2 litres to get enough yeast to pitch at lager fermentation temp ie. around 10 - 12 degrees. Well I have just a bit under 2 litres in a flagon and after 6 days at room temp its still bubbling away but only has about 3mm yeast cake on the bottom (mainly around the outside as the bottom of the flagon is concave).
- Is there any rule of thumb in regard to the amount of yeast cake is enough?
- Should I decant some of the wort off and top up with fresh to try and get more yeast.... or tip some in another vessel and make a second starter.
- When I read about starters they seem to say that a starter should only need 4 - 5 days at most. Mine seem to go on for a week or more. So how long should it take at room temp (18 - 20 degrees) to finish.

I prefer to put in fridge after its done and let it settle and pour off the unspent wort and just pitch the slurry.

advice would be appreciated

Eddy

 

[Thirsty Boy]

It being "fully" fermented is not something that has to happen. You want the cell count to be maximised - it doesn't particularly matter whether the sugar is all eaten up or not.

If you are running up from a slant in the correct increments (5 times volumes steps for a lager yeast), then you should be hitting maximum cell density after about 24hrs or thereabouts - So much after that you can just crash it in the fridge to settle out the yeast. Assuming as you said, that you aren't keen on pitching such a large amount of starter into your beer. You may have to crash it pretty hard to drop actively fermenting lager yeast though.

IMO - there is basically no full sized batch of lager that you plan to cold pitch - where any starter less than 2L would be sufficient (optimum). Unless you are making light beer, 2L is as small as you could possibly go. And that's if you grow your starters on a stirplate. Starters in a jug with some intermittent shaking perhaps - the minimum would be more like 3-4L to get to optimum pitching rates.

 

[edddy57]

Thanks Only done in three increments (50ml, 500l up to just under 2 litres). So looks like I will need to make some more starter. Being a Danish lager yeast means its slow to floc.... so looks also like I will have to crash it pretty hard as well.
Eddy

 

[Rodolphe01]

The last lager I did was pitched with an 8 litre starter. No stir plate though, so the growth rate was pretty low. Fermentation took off like a rocket

It'll be my last lager for a while, although I like drinking them, I really REALLY dislike the waiting!

I use 2 litre starters for my ales FWIW.