Lager fermentation lag time?

[Daniel Ashman]

Hi all,

I brewed my first all grain (BIAB) lager on the weekend. It's a Pilser. Used all Bohemian Pilsner malt and Lubelski hops. Came out at 1.046 OG and 27L. A little under what I was aiming for but not too bad.

My issue is I pitched the yeast on Saturday night and now over 36 hours later I am still seeing no signs of fermentation (no activity in the blow off tube). I am starting to get a bit of a yeasty smell when I open my fridge now though. My question is what sort of lag times should I be expecting and should I be worried?

Some further info:

I made a yeast starter using 2 packets of Mangrove Jack's M84 Bohemian dry lager yeast and a bit of yeast nutrient into 2L of 1.045 OG starter wort. I have a stir plate and put this in my fermentation chamber at 20degC. Unfortunately about 8 hours after pitching the yeast into the starter my fridge stopped working so the starter was at room temperature (high 20s) for about 12 hours before I could fix it. I then cold crashed the starter to 2degC after about 26 hours from pitching for 14 hours. I then decanted it down to 500mL the next day. I then left the starter in the fridge at 14degC during brew day.

My main issue was I struggled to get the temp of my Pilsner wort down to pitching temp, even after cooling in an ice bath then putting it in my fridge. Several hours later it was still well above my desired pitching temperature and I was getting worried about having the wort sitting round in the fermenter too long without pitching. I also wanted to go to bed so I pitched the starter at around 20degC (much higher than I wanted). It took about 6 hours over night for the fridge to bring it down to 12degC.

I stirred the wort for quite a while to aerate before pitching so I think I should have got enough oxygen in there.

Could having the yeast starter too warm for a while or pitching cooler yeast into warmer wort have upset the yeast too much and caused some issues? Obviously it wasn't the plan.

Sorry for the noob questions.

[Mark Weusten]

Hey Daniel, how did this turn out? I know its over a year ago but I am having the same issue with this yeast. Homebrewers deserve to know if this yeast is a dog as there is not much info out there. Cheers

[Daniel Ashman]

Hi Mark,

I played around a bit with the seal on my fermenter lid at the time and it seemed to get going after that. Not sure if it was that the seal wasn't good or if it just had a long lag time to get going.

At the time I didn't re-hydrate the yeast when doing my starter so that may also have had an effect on how long it took to get going.

I think part of it was just that I was used to fermenting ales which are faster to ferment.

I'll try and dig out my fermentation temperature profile for this beer. I largered it for quite a while. Seemed to turn out good from my limited experience.

I think I over hopped it a bit but that's nothing to do with fermentation.

[Mark Weusten]

Thanks Daniel, glad to hear it turned out well. I brewed last Wednesday the Glacial Pilsner kit, rehydrated the 2 packs of M84 pitched at 20c and set my fridge to 15. Took the lid off yesterday and no krausen, gravity hadn't changed. I contacted MJ this morning who advised me  to raise it up to 15 again. I will try this but I think the packaging should warn about long lag times or the need to make a starter which liquid yeasts recommend.

[Daniel Ashman]

I read that when doing largers you should always make a starter, as the lower temperatures mean you need heaps of healthy yeast cells.

I use brewer's friend yeast calculator:

http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/

[Daniel Ashman]

Here is the fermentation temperature profile I used (after this I bottled and conditioned the bottles at 12degC before starting to drink):

[Mark Weusten]

So cranked up to 15c last night and still no airlock activity this morning. Will check for krausen tonight  and take another gravity and if no change repitch. Brewers friend calculator reckons 2 packets of hydrated dry yeast is spot on for 1.048 lager. Mangrove Jacks support told me to keep the packets in the future so they can trace any problems which is a good call.

[Mark Weusten]

Just checked in on day 6, there is small airlock and krausen. I would make a big starter with this yeast. I took gravity and down to 1.040 tasting distinctly of honey which I have never experienced before....