Historically, caramel malts were produced from green malt in a kiln covered with a tarpaulin. The tarpaulin reduced evaporation as the kiln was heated to perhaps 60°C to 75°C and kept at that temperature for up to 2 hours needed for saccharification of the starch in the endosperm. To dry and caramelize the grain, the tarpaulin would then be removed and the temperature raised up to more than 100°C while the grain was being ventilated.
Caramel Malts, as the name implies, impart a strong caramel flavor to beer, which is the result of an extra stewing process that takes place during malting, usually in a roasting drum, between germination and kilning. In a roaster, the green malt is kept at a temperature between 63°C and 75°C during saccharification (stewing) stage. This ensures that the starch from the endosperm is converted into a sugary liquid that is trapped under the husk. Subsequently, the stewed grain needs to be dried. Nowadays this drying is also done in the roaster.
The liquefied sugars are then caramelized into solid, semi-crystalline, glassy, long-chain, unfermentable dextrins. During this process two different reactions take place: the degradation of sugars into brown colouring caramel products (pyrones, furanones) and Maillard reactions between sugars and peptides (melanoidins). At higher temperatures both reaction products form (High Moluculair Weight) HMW melanoidins which are typical for high temperature roasted caramels.
Because the caramelized sugars cannot be degraded during mashing in the brewhouses, they contribute directly to wort gravity. They are also responsible for malty-sweet flavors, a deep color, a complex aroma, a fuller body and mouthfeel, and improved foam retention of the finished beer.
Medium coloured caramel malts are used in amber ales and lagers, red ales and lagers, Märzenbiers, and bock beers. High coloured caramel malts in Porter and Stouts, low coloured caramel malts as foam improver in Pilseners and lagers. And of course whatever the brewer composes…