By Mike Retzlaff
There are two different browning reactions of which we, as brewers, should be aware. The Maillard reaction is a chemical reaction between amino acids and reducing sugars. This reaction produces melanoidins (plus a number of related compounds) which have distinctive colors, flavors, and aromas. Flavors associated with melanoidins include nutty, malty, and biscuity. They occur during the kilning of barley malts (notably Vienna and Munich), and are found in coffee, bread crust, and other bakery products. Another way to further develop color, aroma, and flavor is to toast the malt in the oven on a cookie sheet. The toasting of malt is well covered by Hank B’s “Strive for Style” article elsewhere on this site.
The second browning reaction is caramelization which is the browning of sugar; a process used extensively in cooking for the resulting nutty flavor and brown color. During this process, volatile chemicals are released, producing the characteristic caramel flavor. Much can be found on this subject in Greg H’s article on “Brewing Sugars III” also on this site. It also occurs in the production of crystal and caramel malts which, again, is well covered in Hank’s article.
Both are non-enzymatic chemical reactions and both are driven by heat. In beer brewing, both melanoidins and caramel can be produced in the kettle during the boil. In the case of Bock, Märzen, and several other styles, darkening of the wort is a good thing. In many other beer styles, it isn’t such a good thing.
Melanoidins are also a side effect of the decoction mash. That’s one of the reasons why many German Weissbier and Kölsch breweries don’t decoction mash anymore or at least reserve it to a single decoction.
I’ve read, and sadly can’t remember where, that some Belgian breweries use these browning reactions to their benefit by simmering a wort for 8 to 10 hours to develop colors, flavors, and aromas that could not be realized by recipe formulation alone. After the long simmering, they hop the wort and bring it to a full boil. At that point, they treat the wort as most any other brewer would.
Phil Markowski (Farmhouse Ales) states that in the case of Saison, the boil lasted for five to eight hours and sometimes up to fifteen hours “due to the generally accepted opinion that beer kept better the longer it was boiled.” It was also common to add lime to the kettle to artificially deepen the color of the wort. Although early brewing literature condemned the practice of adding lime to the kettle, sufficient evidence shows that this was done by some brewers at least until the early 20th Century.
Pierre Rajotte (Belgian Ale) states that “the brown beers of Flanders were boiled for 15 to 20 hours to achieve their color and aromas.”
Brian Smith (CCH member and self-proclaimed Visionary) brewed a SMASH beer consisting of domestic 2 Row barley malt and simmering the resulting wort for 11 hours. He added water to the kettle whenever it reduced by half. He recalls adding water 3 times and topping up the kettle a little toward the end. He then brought the wort to a rolling boil and added hops for the last hour – 12 hours total! The wort turned a dark golden honey color. I can remember the beer and can state that it certainly didn’t look or taste as if it was the result of a simple 2 Row grain bill. Without him telling me what he did, it would be almost impossible to guesstimate the grain bill by sensory perception of the final beer.
A paper presented by R.A. Evans to the Journal of The Institute of Brewing in 1905 contained much info concerning “The Beers and Brewing Systems of Northern France.” This paper included some very enlightening details:
Brewery #1 – 6 hour boil time.
Brewery #2 – Bière Blanche, 1.5 hr. hard boil; 1.5 hr. gentle boil. Bière Brune. 5 hr. hard boil; 5 hr. gentle boil.
Brewery #3 – 12 hour boil time.
Brewery #4 – 5 to 6 hour boil time.
Brewery #5 – 5 hour boil; the beer remained in the copper on the hops from 6 pm to 4 am.
It is interesting to note that the 6 Departments named (Nord, Pas de Calais, Somme, Aisne, Ardennes, and Oise) were the only areas normally producing ales; the other 80 Departments of France producing lagers almost exclusively. Though the paper was based on French brewers, over the years the other major brewing cultures have done the same things.
It seems that utilizing heat, through either or both of the two outlined processes, can be just one more factor in brewing unique beers. These methods can help any brewer to produce great beer. These techniques are well within the ability of any home brewer so think about it, plan for it, and give it a try!