Lager fermentation temperature

I need a beer an a fight.

An old english operator told me that when I was a young engineer and I thought yeah, that sounds like fun.

I’m having a beer right now so only the fight is missing. And here is what I suggest we fight over:

Are you for or against high temperature for lager fermentation?

It all depends on the yeast. If the beer doesn’t have fruity esters or diacetyl from the higher temp, then I don’t see the problem.

Also, what do you consider “high”? I’ve fermented various lagers anywhere from 9C to 15C depending on the yeast used.

We can also have a fight over pitching temperature for lager yeast. :slight_smile: (Pitching at room temp vs fermentation temp.)


I always start around 9-10C for 12-14 days, then raise to 18-20C until fermentation is complete and to clean the beer, 7-10 days later.

I always wondered if that long maturation period at 18-20C is detrimental, producing esters and fusel alcools? I usually have no major issues (except that 24/50 beer sent to Cowtown Yeast Wranglers) but would the beer be even more delightful if matured at lower temperature for a longer period? (Lallemand Diamond lager or Fermentis W34/70)

I think W34/70 is very flexible and you won’t have any issues with it. I’ve done something similar just out of laziness or brewing too late in the spring when the temperature in the brewery no longer drops below 18C. (I usually brew lagers in the winter and early spring when I can keep the brewery closer to 10-12C and then I just turn the heat up for a diacetyl rest.)

Typically after 10 to 14 days, you won’t get off flavour from warming your lager. In fact, you’ll be doing your beer a favour by having the yeast break down diacetyl (if present, not all lager yeasts produce it) and cleaning up the beer a little more. Long term rest is probably best done at much lower temperature though. My diacetyl rests are usually just 2 to 3 days.

Some lager yeast produce more diacetyl than others, so I’ve just take the habit of doing pretty much the same thing time after time regardless of what yeast I’m using. That is, very similar to what you do but with a shorter rest at higher temps.


1 Like

J’utilise principalement les levures liquides German Lager et je suit cette méthode pour la fermentation:

  • 7 jours à 10-12c (selon le range recommandé)

  • jour 8 à 14, je monte de 1c par jour

  • jour 15 à 21, température ambiante 20-21c

  • jour 22 à xx : Lagering 0-4c. Pour moi, 3 semaines minimum

1 Like

A beer and a fight, I like it!

Usually I pitch at fermentation temperature to avoid yeast stress. But that’s text book recommendation, I wouldn’t be surprised that it doesn’t change flavour that much. Fermentation temperature being the bottom range of the yeast recommended temp (usually 10degC)

  • Pitch at bottom temperature range (10degC)
  • @ 2/3 Attenuation, raise +1degC/12h to achieve +4 degC. (14degC)
  • 3-5 days Diacetyl Rest (14degC), Usually until gravity is stabilized.
  • Drop it back to 10degC (-1degC/12h)
  • 2-3 week total fermentation
  • 3-6 week of lagering at -1degC

I’ve heard in a podcast/reading that diacetyl rest is recommended at 2/3 or 3/4 of attenuation since yeasts are still active and off flavor appear more at the beginning of fermentation.

High temp fermentation, I wouldn’t do it just because I’m by the book and I think accumulation of small details make better beer.