Leah’s Beer School: Lesson 20

Pasteurization & Beer 

For over 150 years, pasteurization has been instrumental in extending the storage life of food and drinks. French microbiologist Louis Pasteur developed the process in the 1860s, initially revealing that pasteurization could combat unwanted acidity in wine by inhibiting the growth of unwanted spoilage organisms. Similarly, he found that pasteurization could extend the shelf life of beer by applying heat for a short time. 

Types of Pasteurization 

When it comes to beer, there are two main methods of pasteurization. Bottled and canned beer can be pasteurized by passing through a long, narrow chamber or tunnel where they’re treated with hot water or steam at 74C for a fixed time before cooling. This process, called “tunnel pasteurization,” is a viable option for bottles and cans, but impractical for kegs of beer as they take too long to heat and cool. 

“Flash pasteurization” describes the process of beer being treated by passing through a heat exchanger. In this process, beer is heated in a pipe as it flows from the filter to the bright tank (storage tank). There’s actually a pipe within a pipe. Cool beer flows one way in one pipe, and the heated water or steam flows the other way, giving up its heat by exchanging it with cold beer over a large surface area. The beer is heated to 70C- 72C for as little as 30 seconds before it is cooled. 

Pasteurized v Unpasteurized Beer  

By the 1870s, most breweries were using pasteurization, marking a revolutionary change in the beer industry. Prior to pasteurization, beer would spoil easily and the chance of infection from packaged beer was high. Refrigeration was still uncommon and pasteurization was crucial for long-term storage, mass distribution, and consumption. 

Many craft brewers today opt for brewing unpasteurized beer, as pasteurization equipment is expensive, and rapid heating and chilling tends to dull its flavours and aromas.  Modern refrigeration and brewing technology have made pasteurization less crucial to craft beer production, as many craft brews are meant to be consumed fresh.

Pasteurization has played an invaluable role in enhancing food and beverage safety worldwide. In commercial brewing, it is still key to maintaining stability and consistency, especially in its exported products. Craft brewers, on the other hand, enjoy the benefit of serving fresh, unpasteurized brews – and what’s better than a bright, hazy New England IPA on a hot, lazy summer day?