So Yeah, Dood… #10 At Knock-Out
editor’s note: “So Yeah, Dood” is a regular column by contributor Ryan Boddy which deals with something near and dear to the hearts of many sports fans: beer. The goal is to provide insight into the process by which it is made, and the many ways we enjoy it. This piece is the second in a series.
At mash-out, wort is transferred to a vessel where it is brought to a boil. In this phase of the brewing process, flavoring and preservative agents are added at pre-determined intervals.
In a general sense, this step is easy. You bring the wort to a boil and you dump some herbs into it. Within that framework, however, brewers have some serious decisions to make. Choice of additive, length of boil, and times at which additions are made can all have wildly divergent effects on the final product. Subtle differences in this process can result in making a beer that fits a recipe style, or could cause an outcome more in line with a 40 oz. than your typical craft brewed beer.
There are hundreds of different hop varieties to choose from. The Noble Hops — Hallertauer, Tettananger, Spaltz, and Saaz — are the famous German and Czech varieties used to make Pilseners, Märzens, and Weissebiers. Goldings, Northern Brewer, and Fuggles typically go into British beers like Bass and Newcastle. American cultivated hops are typically fruity, floral flavor giants. Cascade, Chinook, and Crystal hops all impart flavors distinct to American craft-brewed beers.
Once a type of hop is chosen, there’s also what form to use the hops in. Plugs, pellets, whole leaf, dry or fresh, each form has an effect on the product. A fresh hop is very similar to the use of fresh herbs in cooking. They don’t keep well and lose flavor over time in the finished product, but used correctly impart a much more pungent, fresh aroma than dry. Dry hops behave like dried herbs, with a little bit going a lot farther than the fresh. Certain beers —like Lambics— even call for the use of oxidized, spoiled, cheesy smelling hops.
The wort is brought to a boil and the initial bittering hop addition is made. This essentially provides a preservative backbone for the beer. Hop oils naturally prevent beer spoilage to a certain degree, while allowing brewing yeasts to thrive. In the past, agents ranging from spruce tips to wormwood were used for the same purpose. Usually with a few minutes left in the total boil time, another, usually smaller addition will be made. This provides the majority of hop flavor to the beer while an addition made at knock-out —when the heat is removed from the kettle— provides the familiar hoppy aroma of finished beer.
Some American brewers have taken to drastically altering this traditional boil structure in attempts to break out of conventional styles. Dogfish Head Brewing in particular works in creating “extreme” beers. Their 60, 90, and 120 minute IPAs are continuously hopped, producing a much more pronounced aroma and flavor profile.
Other herbs can also be added to achieve different characters during the boil. Beers like Blue Moon and Hoegaarden use curaçao orange peel and coriander to achieve a more floral, citrus character. Seeds of paradise, liquorice root, and numerous other spices can be used as well.
The wort is held at a rolling boil for a pre-determined time. Usually, the boil is closely attended in order to prevent boilovers, and a timer is monitored to ensure hops are added at the correct intervals. The longer a wort is boiled, the more intense the flavors become. Think about steeping tea — the longer you leave the bag in, the stronger the flavor gets.
However, the boil doesn’t just allow for the addition of preservative and aroma/flavoring agents. The boil has a significant effect on the beer’s eventual clarification. Even without adding a clarifying agent like Irish Moss or isinglass during the aroma hop addition, the wort will go through what’s called a “hot break” in which proteins denature and coagulate at a certain temperature. Another break, “a cold break,” happens when the wort cools off, allowing the brewer to leave undesirable, nasty tasting particles behind before pitching yeast and fermenting.
Which we’ll get to next installment.