Better Brewing Through Chemistry
Improving Brewing with Chemical Principles
From the standpoint of patent law, brewing could be divided into three categories of invention. These categories are as follows: compositions, processes, and devices.
Notably, each category of invention includes some sort of chemical component. Each Ingredient, intermediate, and finished product could be viewed as chemical composition. Processes describe making or using those compositions (for example the steps in a recipe). Equipment is used to manipulate or measure those compositions (for example, the carboy, funnel, airlock, etc.).
In an earlier article, we discussed patenting beer technology. We noted that craft brewing is filled with innovative people, bound to rapidly improve this technology. In this article, we discuss a chemist’s view of using two “kits” for home brewing. The first kit is Rogue’s Brutal IPA using the Beercraft kit. The second is Brewer’s Best Double IPA. Both were brewed using the Brewer’s Best equipment kit. The kits and equipment were purchased from Sound Homebrew in Seattle, Washington.
Brewing Process Steps from a Chemical Standpoint
Chemically speaking, the brewing process can be broken down into these fundamental steps:
- EXTRACTING — Grain is steeped in warm-hot water, extracting certain components of those grains into the water, creating a “tea”.
- DISSOLVING — Sugar (provided as malt extracts) is dissolved in the boiling tea, creating a “wort.”
- EXTRACTING — Hops are boiled in the wort for varying lengths of time, extracting certain components of those hops into the wort.
- PHYSICALLY MANIPULATING —The wort is transferred to a fermenter and cooled. At this stage, some of the undissolved solids may be physically separated (e.g., filtering or decanting) from the wort.
- ADDING BIOLOGICAL REAGENTS — Yeast is added to provide a fermentation catalyst
- CONTROLLING REACTION CONDITIONS — The system is equipped with an airlock, isolating it from the surrounding atmosphere, thereby controlling the reaction conditions.
Each of the above steps requires the brewer to follow people-sized instructions with the hopes of producing favorable microscopic results. The brewer adds tangible amounts of water, grains, sugars, and hops to a pot. The brewer monitors the clock on the wall and the thermometer in the brew pot. The brewer’s ultimate goal is producing an aqueous solution of molecules (beer) that is pleasing to drink.
Practically speaking, brewer can follow people-sized recipes and produce good beer with reasonable reproducibility. Nevertheless, thinking about the underlying chemistry may provide some sources for future innovation. The rapidly growing craft brewing community seems to be constantly looking for new and different beers. Our hope is that focussing on the chemical underpinnings of brewing will create opportunities for making inventive beers.
Brewing Chemistry – Molecules, Time, Temperature, and Concentration
Brewing beer is chemistry. Generally speaking, the progress of a chemical reaction depends on (1) the chemical regents, (2) the reaction time, (3) the reaction temperature, and (4) the reagent concentration. The term “chemical regents” refers to the molecules in the reaction. Different molecules behave differently. Accordingly, the most important part of chemistry is understanding what molecules are in the reaction. Chemical reactions proceed more rapidly at higher temperatures and higher concentrations.
Chemical Reagents in Beer Compositions
The craft brewing community recognizes the importance of chemical reagents. In particular, extreme brewers recognize the benefits of trying new combinations of ingredients in order to create different flavors. Note, an “ingredient” to a brewer is a “chemical reagent” to a chemist.
One opportunity for further innovation in the craft brewing space could come from viewing the ingredients at the molecular level. By understanding which molecules correspond to certain flavor properties, a brewer could control the reaction conditions to select for desired flavor properties. The brewing community appreciates the molecular composition of certain ingredients during the hopping process. Different varieties of hops are described in terms of their molecular compositions (alpha and beta acids). Those hops are added to the boils at certain times in order to control how they convert into certain flavors.
Craft brewers should not limit themselves to thinking about hop chemistry. Each other ingredient added to the beer also has a molecular composition. Many of those molecules change and react during the brewing process. For example, many ingredients react with the oxygen while being heated (in the boil) in the presence of oxygen (in the air).
Oxidation Chemistry in Brewing
Another potential opportunity for creating new beers could come from a better understanding of oxidation. Oxygen is present throughout the brewing process. Oxygen from the air reacts with many of the ingredients, chemically changing those ingredients to provide different flavors. Additionally, oxygen is an important part of the initial fermentation process.
Thinking about how certain chemical ingredients react with oxygen could provide new ways to make different beers. For example, the concentration of oxygen could be controlled rather than relying on the amount naturally present in the air. One idea would be performing certain brewing steps under and inert atmosphere, by using nitrogen or argon. By limiting the amount of oxygen present, the brewer could control how much certain flavor molecules oxidize. Adjusting the amount of oxidation during brewing could lead to new flavor opportunities. Limiting oxygen could also create opportunities for using higher temperatures and longer times without the negative oxidative reactions. These sorts of techniques could give rise to new beer technology.
Oxygen is an important part of the fermentation process. In Extreme Brewing, Sam Calagione advises that a homebrewer introduces oxygen into the wort by “rocking the baby” before sealing the fermenter. Notably oxygen is also present in the headspace of the fermentation vessel. By varying the amount of oxygen present at various stages of fermentation, the brewer could improve the progress of the reaction.
The Llamas’ Brewing Company in Washington state appears to be the first company doing work in the air-free brewing space.
Chemical Concentration in Brewing
Lastly, a better understanding of concentration could provide some advantages to the home brewer. Molecular concentration is extremely important in a finished beer. For example, alcohol by volume (ABV), international bittering units (IU), a variety of aromatic compounds, and residual sugars play an important role in the beer’s flavor profile. These important metrics are reported to 2 or 3 significant figures. For example, the ABV in Great Divide Brewing Co.’s Hercules Double IPA is reported at 10.0% (three significant figures). Not 10% (one significant figure). Despite the importance of concentration, many beer recipes treat concentration as relatively unimportant.
Concentration refers to the amount of a given molecule within a given volume. (The standard is “moles per liter,” which is called the Molar concentration). In the laboratory, all mass quantities are converted into moles in order to understand the number of molecules. Then, for solutions, the concentrations are described as molar concentrations, to indicate the number of moles per liter of volume. In the home brew beer recipes, the volumes used to make the beer are “approximate” and also imprecise.
Many beer recipes treat volume with relatively litter precision. For example the Brewer’s Best Double IPA recipe instructed the brewer to bring the volume in the fermenter to “approximately 5 gallons” before pitching the yeast. Additionally, the glass carboys available at the Sound Home brew store did not provide any volume indicators. Some very simple improvements to home brewing equipment could be made by providing better volume indicators on the apparatus and paying closer attention to volume.
Please let us know what you think….
Our firm specializes in chemistry and chemical patents. But, we are relatively new to home brewing. Please feel free to use the comments section (below) to offer your thoughts on applying chemistry to the brewing arts.