If you are ready to make the leap from room temperature ale production to temperature-controlled lager fermentation, you'll need a second-hand refrigerator, an analog or digital over-ride thermostat and your normal double stage fermentation equipment. Below you will find a few tips for the beginning lager brewer:
1. Make a yeast starter. Lagers and strong beers need more viable yeast than regular strength ales. Strong lagers need a massive amount of viable yeast.
2. Brew your beer in your usual manner. Try to chill the wort down to 65 - 70° F before pitching the yeast. Aerate your wort very thoroughly.
3. Allow the wort to remain at that 65 - 70° F range until you can see visible signs of fermentation (e.g. the air lock is beginning to slowly bubble). This typically takes over night (~12 hours) or so.*
4. Once fermentation has begun, drop the fermentation temperature to 48 - 55°F for most lagers.
5. Allow the fermentation to proceed at that 48 - 55°F range until fermentation tapers off to a point to where there is very little noticeable activity.
6. Check the specific gravity of the beer. It should be near the predicted final gravity for the recipe. If not, warm the beer up by 3 - 5°. This should kick it off, again.
7. Once the specific gravity is within several degrees of the predicted final specific gravity, raise the fermentation temperature to 62 - 66°F. This is referred to as the diacetyl rest. Its purpose is to squeeze the last bit of fermentation out of the wort, thereby reducing any remaining diacetyl (a naturally occurring compound that makes the beer tastes like butter or butterscotch) left in the beer.
8. After one to three days at this raised temperature, and the fermentation seems to be done, rack (syphon) the beer into the secondary fermenter. Immediately drop the temperature down to about 50°F.
9. Lower the aging temperature about 3°F per day until you’ve reached 32°F. Some brewers swear by crashing the temperature immediately to 32°F, bypassing the gradual reduction in temperature.
10. Age the beer at near freezing temperatures for at least a month. A good rule of thumb is to plan on lagering (cold-storing) the beer for one week for every .010 specific gravity points of original gravity. For example, if the original specific gravity was 1.060, then plan on lagering the beer for six weeks.
11. If you are bottling, syphon your fully lagered beer into the priming bucket, adding the 3/4 cup priming sugar (or 1 1/4 cups of dried malt extract) dissolved in boiling water. We also recommend that you rehydrate a package of dried lager yeast in a half cup of lukewarm water for ten minutes, then mixing this yeast solution into the fermented beer/priming sugar solution. Mix thoroughly and bottle in the usual fashion. Leave at room temperature for 24 hours before chilling down to 48 - 55°F for carbonation. Once beer is fully carbonated, chill to 32°F until you drink it.
12. If you are kegging, simply syphon beer from secondary fermenter into soda canister and immediately force carbonate.
13. Beer should be ready to drink as soon as it is carbonated.
* If re-pitching yeast from a previous batch, you may proceed directly to the fermentation temperatures at 48 - 55°F and adding the yeast, thereby bypassing the starter and the initial room temperature phases.