Fermenting at the low range vs. the high range

I have a dopplebock going right now, has had a nice head of Krausen since Sunday night but I have it in a sump pump room that is 45 degrees. Right now it is fermenting at 48.

I am using Wyeast Bavarian Lager which last time I checked had a temp range of 48 – 55. Can there be a flavor difference when fermenting at one extreme ort the other or is it more of a length of time to ferment thing?

Preferences?

It’s both. Yeast will produce different flavors depending on which side of the temp range your on. Going to the manufacturers website should tell you what to expect. Wyeast (what I use) will tell you what the yeasts characteristics are and usually will tell you what effect elevated temps will have. I generally ferment at the lower end of temp range, unless I’m trying to get a certain flavor like from a wheat or saison yeast.

Colder temps will keep fermentation under control. Slow and steady. Where higher temps will speed up the yeast and the fermentation, but also create more off flavors.

If you’re past high krausen you can increase the temperature with minimal flavor impact. That’s SOP in most lager breweries. Once I get past ~50% ADF, I’ll bump the temp up to 59°F to finish the beer out faster.