Of the many conditions that can affect the color and flavor of wort post-mash, the way in which the boil is executed can have the greatest influence. Degree of caramelization and melanoidin formation can be controlled rather expertly in the kettle by the duration, intensity and timing of the boil. Malliard reactions are a convoluted series of chemical changes in the presence of heat that causes browning and the combination of sugars and amino acids into melanoidin complexes. During this process, there are hundreds of compounds created that have flavor attributes different from the original components. Baked and roasted foods are examples of important culinary transformations. Vienna and Munich malts can do the same thing during the toasty kilning.
Caramelization is the darkening, and consequential flavoring effect that heat has on sugar, and can also be enhanced in the kettle. Caramel and melanoidin formation occur during any boil to some degree, but the key is to either minimize (pale beer) or maximize the formation (dark beer) for the desired effect. The best way to maximize is to intensely boil the first couple of gallons of wort until a noticeable darkening occurs. I like to do this for about 15 minutes before continuing the runoff. The first runnings are the strongest, increasing the interaction of the sugars and amino acids. Alternatively you can darken and concentrate the wort with a longer or more intense boil or both. For bocks and barley wines, start your boil after collecting two gallons of wort. Boil during the entire running of the wort, and another l hour during the hop additions. This prolonged boil of 2 to 3 hours will move your light-colored beers towards amber and your amber beers towards brown. It will contribute a host of flavors and complexity, and make efficient use of your malt.
The versatility of base malts will come as quite a surprise to those who haven’t contemplated making single malt brews before. The variety of these malts combined with the dozens of hop cultivars and yeasts and paired with deft mash and kettle technique leads to a virtual explosion of possibilities. Even within the realm of classic styles, the types of beers that can be made from Pilsner malt, for example, are extraordinarily broad. Of course, some combinations of the three base ingredients are seemingly made for each other. English pale ale malt, East Kent goldings hops and a characterful English yeast is a sublimely simplistic trinity. Likewise, Vienna malt, Halletauer or Tettnang hops and Bavarian bottom-fermenting yeast will make any lover of amber lagers swoon. SMASH beers such as these are the zenith of single malt brewing, but single malts are also an excellent way to demonstrate hop profiles or yeast imprint. Below are a few suggestions using the common base malts and classic beer styles that can be made from each. All of the base malts mentioned below are equipped with enough diastatic power to convert themselves over the course of a normal mash period of one hour (Lovibond specs are approximate). Even malted wheat (2.0 to 3.0°L) offers the opportunity for a single malt beer, but go heavy on the rice hulls in the mash to aid lautering.