Ask Mr. Wizard

Bottle Conditioning Lagers


Nic Ashley • Raleigh, North Carolina asks,

I’ve been brewing ales for a while and want to try my hand at a few lager recipes I’ve created. If I were to do my primary fermentation at 50 °F (10 °C), and my secondary at 45 °F (7 °C), would I have to let the beer warm to room temperature to bottle with priming sugar? I know ale yeast goes dormant in the fridge at low temperatures, but lager yeast thrives in those conditions. So I am not sure if the bottles would carbonate at a temperature range between 40–50 °F (4–10 °C)?


Since you are new to brewing lagers, I would focus 100% of my attention to primary fermentation and how the yeast behaves when fermented at cooler temperatures. Ale brewers are accustomed to having aggressive behavior during primary fermentation and the aroma coming from the fermenter is usually quite nice. Lagers are a different creature all together. Lager fermentation activity is often perceived by the eye as weak, and aromas like rotten egg and burning match are not uncommon. These two features often take some time to get to know. It’s important to have some experience so that you know what works.

So your first priority is to get your hands around the primary fermentation so you recognize “normal” from “odd” and so you know what times and temperatures seem to work for the strain or strains you select. I would not get worked up about bottle conditioning because the strain used in bottle conditioning typically has very little effect on beer flavor; there is simply so little sugar that is metabolized by the yeast during conditioning that the small amount of flavor compounds excreted from the cells during that stage of the game pales in comparison to what is produced during the primary fermentation. Some yeast strains added for conditioning, like Brettanomyces, are a different story and can have dramatic effects on beer during extended aging.

If you feel more comfortable adding a small amount of ale yeast and conditioning at room temperature, I would go ahead and do that — knowing that you are in the stages of learning. If you want to go full throttle from day one and naturally carbonate with lager yeast, that will work, too, since historically carbonation was one of the several important changes that occurred during lagering. The thing that you do need to bear in mind is that when lager brewers use the kräusen method they add fresh yeast after primary fermentation is complete, which helps fermentations finish and also helps for a more rapid and effective maturation process. If you do not kräusen you probably should consider adding a small dose of fresh yeast when bottling (about 20 mL of yeast slurry will provide around 1 million cells/mL) and consider conditioning at room temperature to make sure that your beer comes into condition.

Response by Ashton Lewis.