Roger (Rughi) PMed me the following question, and after I replied, suggested that I post it as a thread.

As far as I know, whiskies use almost exclusively un-malted wheat and/or rye (Fritz notwithstanding), and beers use almost exclusively malted wheat and/or rye (when they use them at all).

Do you know any examples where this doesn't hold true in brewing? If so, are any special measures taken to ensure full conversion?
There are some classic beers that are made with unmalted grains

Belgian witbier, or white beer, is made with about 50% unmalted wheat, and a perhaps a bit of raw oats as well (and some spices such as coriander, orange peel, and a mild lactic-acid tang). Traditionally, a multi-hour, intensive mash, called a turbid mash, was used, but this is not necessary with today's high enzyme malts.

It is an ancient style of beer, but like many old European ales, it nearly went extinct. Then in the '50s (I think), Pierre Celis resurrected it with the brand Hoegarten, and it became a success story. He sold the business to Interbrew in the 80's (I think), moved to Austin, Texas, and began brew the same beer under his own name. He sold to Miller in the 90's, who overextended the brewery distribution and quit brewing it. In 2002, they sold the brand, equipment and recipe to Michigan Brewing Co. just up the road from me a few years ago.

Although it isn't wheat or rye (which was your question, but I think you were not intending to restrict your question to that), another classic style that uses unmalted grain is dry Irish stout, as typified by Guinness. Guinness uses 20% raw barley. This was probably done originally to avoid taxes on malted grain, and, besides, raw barley is cheaper than malted. But in this case, as with so many, necessity resulted in a style characteristic - Irish stout is drier than an all-malt one would be. Even with relatively low-enzyme Irish or UK malt, there is plenty of enzymatic activity to convert the extra starch.

Then there is one extremely popular style which uses unmalted grain that you might not have thought of because it is so ubiquitous (though not highly regarded among connoisseurs) - American lagers. This style, which is probably the biggest selling beer in the world, uses 30-50% unmalted corn or rice (although many use brewers corn syrup now).

A special double mash technique was worked out in the 1880's to accomodate these grains. This is necessary because corn and rice starch do not gelatinize at mash temperatures as barley, rye and wheat starches do.

This technique, called the American double mash system, is similar to the manner in which corn is used in bourbon. The corn or rice is mashed briefly with about 10% malt, and then this is boiled. Then the rest of the malt is mashed, and after a rest, the boiling hot cereal mash is added, which boosts the mash temperature to a second step.

There is a common prejudice among homebrewers and beer geeks in general against beers which do not meet the Bavarian purity code Reinheitsgebot, which prohibits unmalted grain, but to be rigid about this would eliminate many fine beers.