What are ales?
Ales are brewed with "top-fermenting" yeasts at close to room temperatures, 50-70F (10-21C). Ales encompass the broadest range of beer styles including bitters, pale ales, porters, stouts, barley wines, trappist, lambic, and alt. The British Isles are famous for their ales and it is a popular style with homebrewers and micro-breweries.

What are lagers?
Lagers are brewed with "bottom-fermenting" yeasts at much colder temperatures, 35-50F (2-10C) over long periods of time (months). This is called "lagering". Lagers include bocks, doppelbocks, Munich- and Vienna-style, Maerzen/Oktoberfest, and the famous pilsners. Pilsner beer originated in the town of Pilsen, now in the Czech Republic and was the first non-cloudy beer. Most popular beers produced by the large North American breweries were originally of the pilsner style. These have diverged a great deal from the original style and succeed now by the force of the mass-marketing prowess of the brewers rather than any remarkable qualities of the beers themselves.

How are they different?
The differences tend to be based on tradition more than anything inherent to either style. The major traditional differences are a result of the varying lengths of fermentation and temperature used for the two beer types. They can also vary in style and degree of hopping and in the types of malt used, but these differences are very arbitrary and exceptions abound.

Ales generally undergo short, warm fermentations and are intended to be consumed soon after completion. The result of relatively warm fermentation is that a lot of by-products of yeast metabolism besides alcohol and CO2 get left in the beer. These usually manifest themselves as "fruity" or "buttery" flavors which vary in degree and flavor with the strain of yeast used and the temperature and duration of fermentation. Accordingly, ales exhibit their most complex flavors when served at warm temperatures, around 50-60F (10-15C).

The trick with lager yeast is that they can survive, metabolize, and reproduce at lower temperatures. Lager yeast can assimilate compounds which ale yeast cannot, fewer by-products are made, and the stuff that does get made drops out during lagering. The result is a very clean, sparkling beer. Lagers are best served at slightly cooler temperatures than ales, 40-50F (5-10C).

Of course there are notable exceptions:

California Common
The best known example is "Steam Beer" which is a trademark of the Anchor Brewing Co. It employs lager yeast fermented at ale temperatures which gives it some fruitiness usually associated with ales.

Koelsch and Alt
Ales that undergo a cold secondary fermentation and storage period resulting in only a hint of ale-like fruityness. Koelsch is usually associated with the city of Cologne, Germany while Alt is indigenous to Duesseldorf.

Cream Ale
Alternately, an ale fermented at lager temps or vice-versa. It has also been made by blending a conventional ale with a conventional lager after fermentation. Most examples are only slightly more interesting than mega-brews; a touch more body, a touch more fermentation flavor.

What are lambics?
Lambics are a type of ale brewed in parts of Belgium by exposing hot wort (unfermented beer) to the outside air. Indigenous, wild yeasts and other microorganisms settle on the exposed surface of the wort as it cools and begin spontaneous fermentation. They are often sweetened with fruit flavorings and generally prized the world over.

What is "bock" beer?
Bock is a style of lager beer which originated in Germany. It was traditionally brewed in the fall, at the end of the growing season, when barley and hops were at their peak. It was "lagered" all winter and enjoyed in the spring at the beginning of the new brewing season. Bocks can be pale (helles) or dark (dunkles) and there are double(doppel) bocks which are extra strong.

Bocks are usually strong beers made with lots of malt yielding a very full-bodied, alcoholic beer. A persistent myth has been that bock beers are made from the dregs at the bottom of a barrel when they are cleaned in the spring. This probably seemed logical because of the heavier body and higher strength of bocks. From a brewing standpoint, this is clearly impossible for two reasons: 1) The "dregs" left after fermentation are unfermentable, which is exactly why they are left over. They cannot be fermented again to make more beer. 2) Any attempt to re-use the "dregs" would probably result in serious bacterial contamination and a product which does not resemble beer as we know it.

What is "porter"?
From: The Guinness Drinking Companion by Leslie Dunkling (1992) Guinness Publishing; ISBN 0-85112-988-9 "In the London Ale-Houses and taverns of the early 18th Century it was common to call for a pint of "Three threads", meaning a third of a pint each of ale, beer, and twopenny (the strongest beer, costing twopence a quart). A brewer called Harwood had the idea of brewing a beer that united the flavours of all three. He called this beer "Entire". This was about 1720.

Harwood's Entire was highly hopped, strong, and dark. It was brewed with soft rather than hard water. Within a few years Entire was also being referred to as "Porter" (short for porter's ale) because the porters of the London street markets were especially fond of it. Porter that was extra strong was known as "Stout Porter", and eventually "Stout"."

What are "dry" beers?
"Dry" beer was developed in Japan. Using more adjuncts (like corn and rice) and genetically altered yeasts, these beers ferment more completely and have less residual sweetness, and hence less aftertaste.

What are "ice" beers?
The making of "ice" beers, in general, involves lowering the temperature of the finished product until the water in it begins to freeze and then filtering out the ice crystals that form. Since water will freeze before alcohol, the result is higher alcohol content. The ice forms around yeast cells, protein particles, etc. so these get removed as well; leaving fewer components to provide taste and character.

This process is not new to brewing, having been developed in Germany to produce "eisbocks". Apparently they were produced by accident during the traditional spring celebration with bock beers. Spring, being the capricious season that it is, probably sent a late cold snap around one year causing some of the spring bocks to partially freeze. People drank it anyway and liked the change in flavor.

In its current incarnation, the process is an offshoot of the concentrated fruit juice industry. It was developed by orange growers to reduce the costs of storage and shipping by concentrating the fruit juice through freezing and removal of some water. Labatt Breweries claims to have pioneered this process for brewing and most of the large North American brewers quickly followed suit in the usual marketing frenzy.

The main difference between these "ice" beers and true eisbocks is taste and character. Any beer brewed using this method will only be as good as the brew with which you start. In other words, if you start with a bland, flavor-impaired, adjunct-laden beer and remove some of the water, you end up with a bland, flavor-impaired, adjunct-laden beer with more alcohol. OTOH, if you take a rich, malty, traditionally brewed bock and remove some of the water, you end up with an eisbock.

What are "cold-filtered", and "heat pasteurized" beers?
Cold-filtering is a way of clarifying beer with a shortened lagering time. Beer (lager particularly) becomes clearer with extended storage which allows proteins and other particles to coagulate and settle out of suspension. The beer can then be drawn off and bottled. One way to reduce the time required is to chill the beer causing these molecules to "clump" and be easily filtered out. The up-side is that the time from brewing to finished product is shortened, thereby boosting productivity. The down-side is that cold-filtering also removes many components which contribute flavor and body to beer.

Heat Pasteurized is a redundant phrase since pasteurization means heating to kill microbes.

Some beers are bottle or cask conditioned, meaning that live yeast are still in the beer in its container. Most mainstream beers are either filtered, to remove all yeast and bacteria, or pasteurized to kill all yeast and bacteria. This makes for a more stable product with a longer shelf-life.

Pasteurization is more expensive and tends to alter the flavor. Filtration is cheaper, leaves a clearer beer, and has less effect on flavor.

The "ice" beer process (see above) enhances filtration schemes because more stuff can be filtered out more quickly using less filtration material which shows up directly on the old bottom line.

What is "draught" (draft) beer?
Technically speaking, draught beer is beer served from the cask in which it has been conditioned. It has been applied, loosely, to any beer served from a large container. More recently, it has been used as a promotional term for canned or bottled beer to try to convince us that the beer inside tastes like it came from a cask. See also "Real Ale".

How is specific gravity related to beer?
Specific gravity is a measure of the density of a liquid. Distilled water has a specific gravity of 1.000 at 60F(15C) and is used as a baseline. The specific gravity of beer measured before fermentation is called its Original Gravity or OG and sometimes its Starting Gravity (SG). This gives an idea of how much sugar is dissolved in the wort (unfermented beer) on which the yeast can work. The range of values goes from approximately 1.020 to 1.160 meaning the wort can be from 1.02 to 1.16 times as dense as water (in British brewing the decimal point is usually omitted). When measured after fermentation it is called the Final Gravity (FG) or Terminal Gravity (TG). The difference between these two values is a good gauge of the amount of alcohol produced during fermentation.

The OG will always be higher than the FG for two reasons. First, the yeast will have processed much of the sugar that was present, thus, reducing the gravity. And, second, the alcohol produced by fermentation is less dense than water, further reducing the gravity. The OG has a significant effect on the taste of the final product and not just from an alcoholic standpoint. A high OG usually results in beer with more body and sweetness than a lower OG. This is because some of the sugars measured in the OG are not fermentable by the yeast and will remain after fermentation.

Here are some rough guidelines:

Some Bitters, Milds, Wheat beers, and most "Lite" beers have an OG ranging from 1020-1040. The majority of beers fall in the 1040-1050 range including most Lagers, Stout, Porter, Pale Ale, most Bitters, and Wheat beers. From 1050-1060 you'll find, Oktoberfest, India Pale Ale, ESB (Extra Special Bitter). In the 1060-1075 range will be Bock, strong ales, Belgian doubles. Above 1075 are the really strong beers like Dopplebocks, Barleywines, Imperial Stouts, and Belgian trippels and strong ales.

What does "Dubbel" mean on a beer label?
Belgian ales often carry additional wording on their labels indicating their strength. This applies to their original malt strength not their alcoholic strength. Variations may appear as follows:

• Single:
  Dutch/Flemish - enkel (pron. 'ankle')
  French/Walloon - ?
• Double:
  Dutch/Flemish - dubbel (pron. 'double')
  French/Walloon - double (pron. 'doobluh')
• Triple:
  Dutch/Flemish - tripel (pron. 'treepel' or 'trippel')
  French/Walloon - triple (pron. 'treepluh')
• Quadruple:
  Dutch/Flemish - quadrupel (pron. 'quadruple')
  French/Walloon - quadruple (pron. 'quadrupluh')