Weird lager fermentation temps

[Professional beer tester]

Hi all,

Have had two lagers sitting in the fermenters for about 10-11 days. Room temp was around 13-15º, but I forgot to add 2ºC to the actual fermentation temp.

Initial fermentation was quite rapid at 16-18ºC, then after 5 days it seemed to have become 'stuck' at 1025 once I dropped the temperature down to get the ferment temp around 14ºC.

Now I've warmed them up to 18ºC again and they're bubbling away again.

Is this normal?

Yeast strain is Saflager S23 – wondering if the yeast got used to the higher temp and crashed once it was cooler?

Strange cidery taste coming out of one that has started tasting more and more like lager, awesome beer taste coming out of the other – but both are only 3% from an OG of 1055, really want to finish the batch, just worried about the higher temps.

 

[manticle]

When fermented at the correct temperatures, lager yeasts are slower than ale yeasts so while they ferment at lower temps, they also ferment more slowly. At higher temps they will ferment quicker. Fermentation rates also slow as they move towards FG.

It's likely that your higher temps are just pushing things through quicker, not that lower temps have made it stall. The lower temps are just not producing the same visible signs as the higher. Lamarck might believe the yeast have evolved to acclimatise to the higher temps but i don't.

Generally you should start low and allow to rise slowly till you get to diacetyl rest temperatures. Starting high will create an ester profile that may be inappropriate unless trying for a steam beer.

May as well leave at higher temps now, finish ferment, then drop back and lager for as long as you can stand. Next time pitch plenty of yeast cool (as cool as possible - I start lagers around 4 and allow to slowly rise to 7-10, then bring up once they are about 3/4 the way through to get to 18 (1-2 degree a day) before dropping back to 0 (slowly again).

 

[Professional beer tester]

Sweet, thanks, feeling the need for a fermentation fridge.

Don't mind the old Anchor Steam. Fermenter was stuck @5 days for almost a week on 1025... even tho temps never got down to proper lager-yeast temps... strangely dropped to 1024 overnight at the higher temp...

What temp do you pitch at? If rehydrating in wort as a starter, what temp do you make the wort?

 

[manticle]

I pitch at around 4 as mentioned. I make starters slightly differently to many - I pitch identical wort starters when active so I ferment my starters at lager temps (not 4 but 7-10).

I brewed for several years without a fridge - a water bath is your best bet for keeping a stable temp. Trick is to always pitch into wort that is a few degrees below intended ferment temp and maintain consistent wort fermentation temp for at least the first few days. However the whole 1 degree per day thing is pretty hard without a temp fridge and you definitely want a fridge for cold conditioning/lagering.