I am trying my first batch of lager with Munich malted barley cascade hops. I pitched the lager yeast at a relatively high temp around 25°C. I had oxigenated my wort as it cooled in the boil kettle with pure CO2. I left 40L fermenter in room temp 22°C overnight to let the fermentation start. I had very strong bubbling the next morning. At that point I placed my fermenter in a refrigerator and set temp at 12°C. After a week my bubbling seemed to end in the air lock. I lowered the temp to 5°C and let it rest for another week. My FG was 1.012 and 1.020 after priming.

I bottled and placed in fridge again about 17°C.

My question is: what temp should I keep for getting good CO2 after bottling? Should I have kept it in room temp about 22°C for a day or so before cooling? Beer tasted not too bad but little CO2 before I bottled.

Thanks for all potential answers.

2 Answers 2


OK first to answer your question. If you keep your primed bottled lager at 5C it will take a long time to carbonate up, if you let it sit at room temp for a week, then chill it should be ready in about 8 days.

Also, 1012 to 1020 for priming it would suggest you used about 20g/l of priming sugar, that seems a bit on the high side to me. I would usually prime with more like 10g/l, you may be ricking bottle bomb with that much primiing sugar.

Take a look at these webpages for a better understanding of priming:



Secondly, I would never pitch a lager yeast at 25C, that is a bit high for many lager yeasts and you risk stressing your yeast.

I would pitch a lager yeast more around 20C(A) for a day then lower by ~5C per 12 hours until your desired fermenting temp is reached.

At the end of your 5C fermentation period, you will probably want to incorporate a Diacetyl Rest. Take the FV out of your fridge and allow it to warm to 18C for 2 days; do this when you are about 2 points above FG. Then chill it quickly to 5C, let the beer drop clear, rack/prime/bottle/keg as you wish.

  • Pitching at 25c for a lager isn't bad for yeast health, but will allow it to produce some undesirable growth esters. For example a lager starter is done at room temp for easy and healthy growth. But these starters should be decanted before pitching. May 11, 2018 at 12:02
  • 1
    I agree that the priming sugar is too much, 10 point above TG could make bottle bombs or volcano beers if the bottles hold. May 11, 2018 at 12:05
  • I wouldn't propogate lager yeast above 24C/75F, 25C is not terrible, but as fermentaion gets underway the temperature is likely to creep up and it will stress them, they won't all die off but you are not maintaining optimal conditions. I will reword my sentence to be less dramatic, as rereading it it does sound a biit excessive. It was written before coffee.
    – Mr_road
    May 11, 2018 at 13:24
  • White Labs grows all thier yeast at about 75°F. How the yeast is grown for the initial pitch isn't too critical as that generation doesn't do the fermentation. May 11, 2018 at 13:29

Lagers should be pitched at the strains lowest recommended temperature.

If lager yeast is allowed a warm growth phase that will produce some bad esters. Also the new cells will be prone to favor the temperature they budded in, causing much of them to go dormant earlier than usual if temperature is reduced.

After a cold growth phase lagers can be increased in temperature a couple degrees a day up to 68°F then held there for the Diacetyl Rest. Once done then can be primed and bottled for conditioning at room temp.

This really applies to both ale and lager yeasts. Start low and go warmer if needed. Doing the reverse is bad for the yeast and the beer.

Going 8 points above TG for priming is asking for trouble if not in Champaign bottles. It's almost twice what it should be, and could lead to bottle bombs or volcano beers if the bottles hold.

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