• Welcome to the new forum! We upgraded our forum software with a host of new boards, capabilities and features. It is also more secure.
    Jump in and join the conversation! You can learn more about the upgrade and new features here.

Lager Fermentation duration.

Olla

Apprentice
Joined
May 18, 2015
Messages
7
Reaction score
0
Good day.
Need advice.
I started 2 lager brews, 7 days apart. Both require 12 deg C for fermentation and 4 deg C for carbonation.
On Day 7 of the first batch, brew no. 1 still bubbled happily. Now at day 8 of brew no. 2 (happily bubbling every 5 seconds), Brew no. 1 became "dormant", maybe a bubble every 70 seconds.
I do not want to bottle Brew no. 1 now, it must wait for brew no. 2 so that I can carbonate both at 4 deg C. I use one deepfreezer with electronic temperature control. I do not want to compromise the fermentation process of brew no. 2 to set the temp to 4 deg C and visa verse.
Now the question: Will this be harmful to Brew no. 1 to wait "passively" for Brew no. 2 to finish bubbling.
I don't think so. I feel that brew no. 1 reached an equilibrium between the amount of sugar and alcohol in the fermentor and the yeast is now at rest. Add sugar and/or oxygen = the best will start up again???
How far of the mark am I?

 
It will not harm your No. 1 brew to wait for the second brew to finish.  I would give it a good 5 to 7 days after the bubbling stopped anyway to allow the yeast to clean up any unwanted byproducts.  Adding more sugar at this point would just start No. 1 going again and you would need to wait longer for that to stop.  DO NOT ADD OXYGEN!  This will contribute oxidation flavors in your lager (cardboard, etc.) which you do not want.
 
Thank You, Grandmaster. This would be my 3rd and 4th brews with the GrainFarther.
One thing I learned after tasting the difference between previous brews and the recent one's is that temperature regulation plays an important part in brewing. That is the reason for waiting with the 1st brew, to have both carbonating at the same temp.
Kind regards,
Olla.
 
The "danger" with letting beer sit on the yeast too long is autolysis, where the yeast commits suicide by explosion and adds flavors of burnt tires to the brew. I've let beer sit in the primary for over a month (or two with lagers), and in the secondary for most of a year. I've had them spoil, but not because of that.

One real danger is head space. If there's a lot of space between the brew and the airlock, then temperature fluctuations can cause the air pressure inside to change enough to suck airlock liquid into the brew. This is not good. When you've got active fermentation going on then you've got positive pressure and nothing to worry about. But after it goes dormant for a month, or after you rack it into secondary, then that head space matters.

My point being that you can let it sit around for a couple weeks without worry. Stagger a few brews and bottle it all at once.  Then enjoy!
 
I give my cold fermenting lagers always 3 - 4  weeks in the primary fermentor regardless of when bubbling stops. Lots of time for settlement of all yeast. Then it's kegged , coldcrashed to 35F and carbonated with 30 psi  CO2 for 2  days. Sampling commences, and the beer is usually quite drinkable at this point before any further ageing. Making double batches ensures lots for the aged side.
 
Thank you twitaker.
I have to bottle at this stage, working on the finances for a keg system.
I shall have brew no. 1 in for about 23 days and no. 2 for about 14 days.
 
Back
Top