Appearance of Lager Fermentation

[Pangea]

Well I thought I wasn't a noob anymore... that is until my first lager!

So I've got my first lager fermenting away. It has behaved totally different than all of the other fermentations I've witnessed. Wanted to get input from others that have made lagers if what I'm seeing is normal. I used 2 packs of34/70, just sprinkled into an oxygenated 5.5 gallon batch, OG 1.052. I'm on day 12. Observations:

1. Krausen never really built up like an ale. Didn't get all creamy looking like the usual ale. Just kinda formed a white foam about max 1cm thick. Didn't really push much trub, etc to the wall of the carboy compared to what the krausen does in my ales. (I'm guessing this is normal because the yeast is "bottom fermenting")

2. After 8 days, what foam or krausen was present had started to reduce and fall back into the beer. I raised temp 10 degrees to 63 from 53 for diacetyl rest. I expected an increase in foam due to increase in yeast activity. Instead the airlock gradually bubbled less and less until it stopped 3 or 4 days later. No increase in the amount of foam or krausen, in fact it decreased. (did I start the d-rest too late?) I did not take a gravity reading before performing d-rest. Just eyeballed - the lazy way.

3. Since there wasn't much krausen bubbling up and floating trub to stick to the walls of the carboy, there is still some very small pieces of trub floating on top of the beer. Is this normal? Do lagers create minimal krausen?

4. I can see a very defined yeast/trub cake at the bottom of the carboy. Looks thicker than almost all of the other beers I've done.

I will be taking a gravity reading tonight to see if fermentation has attneuated almost to completion. There isn't any airlock bubbling and there isn't any foam or krausen left. Again, this is day 12 of fermentation.

Thanks in advance!!

Pangea

 

[menschmaschine]

That all sounds perfectly normal. Lager yeasts generally produce less of a krausen. This yeast in particular, for the 2 batches I've brewed with it so far, I've noticed a rather small krausen. It sounds like you're about done primary. I'd start cooling it back down by 5°F per day and rack it to secondary soon.

 

[Pangea]

Thanks. That's good news!

I'm actually going to drop temp as you describe, but leave in primary for another week or two at 34F to settle everything I can. Then I plan to rack into a keg - then lager in the keg for a few more weeks before carbing up and tasting. Hope my method works out because I really enjoy a good pilsner/lager and I'm very nervous about my attempt!

 

[menschmaschine]

Sounds good... except you might reconsider your racking time. A week or two extra may or may not make a difference, but it is generally recommended to get lagers off the primary yeast soon after primary fermentation is complete. It's not necessarily an autolysis concern, but decaying yeast cells can cause slight off flavors in lagers.

 

[Pangea]

Got it. That's good advice. Thanks.

 

[passedpawn]

IMO, 3 weeks in primary is OK for lager. If you are going to truly "lager", say for months, secondary is good idea.

 

[Pangea]

Update - FG measured at 1.013 at day 13 after a few days diacetyl rest. Tasted hydro sample and it has the slightest hint of yeastiness and butter (diacetyl). I think it is so subtle it will go away with lagering. Otherwise the beer was very clean and tasty, which is a great sign. Looks like the 34/70 yeast worked well at about 73% attenuation - even though it never looked like it.