Lager Fermentation Advice Needed

charliemartin · Post by **charliemartin** » Mon Mar 28, 2016 2:33 pm

Just looking for some advice from more knowledgeable lager brewers on the forum. I brewed my first lager 18 days ago. I fermented at 11C for 15 days at which point the SG was down to 1.020 from 1.050. Thought I could detect some diacetyl in the hydro sample and raised the fermentation temp to 18C on 25th March over 24 hours. it has been at that temperature until today when I took another gravity sample and it has dropped 4 points to 1.016.
I fermented with WLP 800 yeast in a 2.5 litre starter and there has been a full krausen on top of the wort since about day 2. Apparent attenuation is currently at 68.0%. I would expect it to ferment out a bit more than that, so should I continue to ferment at 18C or should I drop it back to 11C?
I am planning to rack to secondary after 21 days (in 3 days time) and lager for 4-6 weeks at 4-5C (fridge won't go lower).
Any advice would be welcome.

Cheers,
Charliemartin

Haydnexport · Post by **Haydnexport** » Mon Mar 28, 2016 4:23 pm

I cant really advise on the yeast, ive only ever used w34/70, id personally rack it off the trub/yeastcake, take the temperature down to the max suggested(w34/70 is 15c) and give it another week then take another reading. You can probably knock a week or 2 off the lagering phase by having a cleaner starting lager anyway is what i find.

charliemartin · Post by **charliemartin** » Mon Mar 28, 2016 7:55 pm

Thanks for the reply. Not quite sure what you mean by a cleaner starting lager. Could you explain please?

Haydnexport · Post by **Haydnexport** » Mon Mar 28, 2016 9:48 pm

The yeast will have fermented everything and got rid of any potential off flavors if left longer to do their job, 11c is lower than i brew lager too (12.5c) and sometimes if i havent pitched quite enough yeast it can take longer to fully ferment and have no noticeable flavours such as green apple and the buttery popcorn taste . even when it has reached 1.012 -1.010 i sometimes get it so i just leave it another week, patience is definitely the way with lager i have found.

charliemartin · Post by **charliemartin** » Tue Mar 29, 2016 12:28 pm

Ok, I see what you mean. I did possibly underpitch. Although I made a big starter, I probably didn't make it far enough in advance to let the yeast fully ferment it. I'm used to 1 litre starters for ale fermentation. Think I'll leave it at 18C for a few more days to try and get it finished.

Rookie · Post by **Rookie** » Tue Mar 29, 2016 10:17 pm

All grain or extract? If extract you could be done.
I'd leave it at the higher temperature and give it at least another week.

charliemartin · Post by **charliemartin** » Wed Mar 30, 2016 9:14 am

Hi Rookie, it was all-grain. There's no rush to get this one finished so I will leave it at 18C until it's done, then transfer to secondary.

Jocky · Post by **Jocky** » Wed Mar 30, 2016 9:19 am

charliemartin wrote:Ok, I see what you mean. I did possibly underpitch. Although I made a big starter, I probably didn't make it far enough in advance to let the yeast fully ferment it. I'm used to 1 litre starters for ale fermentation. Think I'll leave it at 18C for a few more days to try and get it finished.

I think you've got the right approach and can't see anything you've done wrong from my brief lager experience.

You need to effectively double the pitch rate of yeast compared to what you would do with an ale, but I don't think you need to ferment out any starter. Personally I just run them for 18-24 hours and pitch as most adaption/growth is done in that time and the yeast is super active. So I think you're fine there.

Fermentation temperature is obviously the other major difference. You'll need to seek out advice for that as it's yeast strain dependent. Personally I like the fast ferment method, whereby you ferment at lager temperature for 5-10 days (or when at at least 50% expected attenuation) and then bump the temperature up to 18C over a few days and leave it there until done.

For my Helles (OG 1.050) with WLP833 I:
Pitched at 9C
After 24 hours: Raised it to 10C
After 6 days: Raised to 18C
13 days: Diacetyl test is negative so drop ambient temperature to 0C.
27 days: Add gelatin (still at 0C - helps precipitate chill haze so the geltin can pull it down)
28 days: Bottle, and then move to room temperature for carbonation/conditioning.

That temperature schedule may be different with your yeast though.

npg · Post by **npg** » Wed Mar 30, 2016 1:32 pm

I pitch at 5C, ferment at 7C, then it's a long conditioning schedule which slowly takes it down to -1C over the next 8 weeks. Pressure is set to 0.5BAR. Cell count should be 15 billion cells per litre.

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