Lagers are a type of beer that is usually light, crisp, and in my opinion, watery. But I digress...Lagering is the process used to make this particular type of beer, and it starts, believe it or not, with the yeast. But before we even get into that, let's go over some basics:
1. Beer has 4 essential ingredients:
* I know, I said 4...we'll get to that in a minute.
2. You start by making a wort, which is unfermented beer. The sweet liquid that you get when you mash grains (grinding or crushing them, see #3 below) and add them to hot water. I say hot, not boiling, because there are so many varying temperatures used by brewers to achieve their special recipe. Be that as it may, you make the wort first. Included in making this wort are the additions of the *Other ingredients I mentioned above. Of course, this must include hops. There are many other things that can be added, gypsum to condition the water ph, irish moss powder, brewers' licorice, etc., but hops are a necessity.
3. Barley is the most common grain used in beers, although some beers like Budweiser use rice in addition to barley. The difference, of course is that lagers and other lighter beers roast their barley very little, and heavier, darker beers, ales such as stouts and porters roast it quite a bit. The roasting imparts flavor and depth along with the deeper, darker color profile.
4. Yeast. Ah, the yeast. It's the last thing to go in, usually, but really the difference in lagers and ales starts with the yeast. What yeast does is eat sugar and convert it to alcohol. The sugars in the wort provide the many different varieties of yeast plenty of food for conversion. A by-product of this sugar-to-alcohol conversion is CO2, which is why the bubbles we all love in our beer is called carbonation.
Lager yeasts flocculate (no, that's not a bad word, you don't have to go wash your mouth out for saying it. It means to gather together loosely) at lower temps towards the bottom of the ferementing tank. The temperature for this ranges from 40° to 55° and takes much longer than fermenting ales does. After fermenting, lagers are aged for months at even lower temps, around 32° to 45°.