advice please

[kerant]

Started a Imperial pilsner yesterday. 6gal, partial mash with llme, extra light dry malt extract and some cara pils crushed malt for the tea. Used dry yeast re-hydrated ( Mauribrew ) , but not thinking when I ordered from my LHBS that this is a Lager I only got 16 gms. When I punched in the #'s on Mr Malty after the fact; it said I need 40 gms. The O.G on the recipe comes in at 1.089; mine came out at 1.095 before adding 1 gal top up water so I think that should be OK. Almost 24 hours later I have a krausen about half an inch ( or is that left over from shaking it up yesterday?? ). I guess after my first 2 partials being excessively lively in fermenting I expected the same with this. Question is do I let it ride or pitch more yeast which I won't be able to get until tuesday? By the way pitch temp was 55f; ferm temp will stay under 50f in my garage and ferm duration is 6 weeks between primary and secondary but I plan on just leaving in primary.
Thanks for your input

 

[jdrowell15]

The majority off flavors created by the yeast due to under pitching will have already happened by the time you get more yeast, so there is no helping that. The important question here is did the yeast multiply enough to finish fermentation. That will depend on how well you aerated. If you only shook the carboy then you only got the minimum.

It will probably be ok, you just might miss your FG by a few points. What I would do is keep an eye on the gravity and buy more dry yeast and if you don't use it you can just keep it on hand in case these things happen in the future, since dry yeast stays good for so long.

You could also help the yeast along by slowly increasing the wort temp during the last 1/3 of active fermentation. 3-4 deg a day. You will want to do this for a diacytal rest anyway, especially since you under pitched.

Good luck!

 

[kerant]

Since this is my first lager can you tell me with fermentation; do they ever do the heavy fermentation or are they usually pretty sedate. I'm wondering because although I have no airlock activity I still have about half an inch of krausen after about 30 hrs.

 

[jdrowell15]

Lager beer fermentation is typically pretty calm, takes longer to start and takes longer to finish then ales. It could be as long as 3 days before you see any activity in the wort or airlock. The fact that you have something like a Krausen on top is a good sign.

An interesting fact I learned from the Brewing Network is that the colder the wort is, or any liquid for that matter, the more CO2 it holds in solution. Part of the reason you don't see any airlock activity for so long. Though the yeast is producing it.