Coolship

Bockorkoelschip

Coolship is a traditional brewing tool used in the production of beer, particularly in the making of lambic, a type of Belgian beer. A coolship, or "koelschip" in Dutch, is a large, shallow, open vessel made of stainless steel or copper, designed for the cooling of wort after boiling. This process is crucial in the brewing of certain types of beer, as it allows for spontaneous fermentation by exposing the wort to wild yeasts and bacteria present in the air.

History

The use of coolships in brewing dates back centuries and is most closely associated with the lambic breweries of the Pajottenland region in Belgium. In the days before mechanical refrigeration, coolships were an essential part of the brewing process, allowing brewers to cool their wort naturally overnight. This method of cooling not only facilitated the inoculation of the wort with wild yeasts but also contributed to the unique flavor profiles characteristic of traditional lambic beers.

Design and Function

A coolship is typically a broad, open-top, flat vessel, which maximizes the surface area of the wort exposed to the air. After the wort is boiled and hops are added, it is transferred to the coolship where it is left to cool overnight. During this time, microorganisms, including wild yeasts like Saccharomyces and bacteria such as Lactobacillus and Pediococcus, settle in the wort and begin the fermentation process. The large surface area of the coolship facilitates efficient cooling and aids in the inoculation of the wort with these ambient microorganisms.

Modern Use

While the advent of modern brewing technology has made coolships less common, they are still used by a number of traditional lambic breweries in Belgium and by craft brewers around the world seeking to produce beer with unique, complex flavors through spontaneous fermentation. Modern coolships are often equipped with features that allow for better temperature control and cleanliness while still adhering to traditional brewing methods.

Coolship and Beer Styles

The use of a coolship is most closely associated with the production of lambic beers, including gueuze and fruit lambics, which are known for their sour and often funky flavor profiles. However, the technique is not limited to these styles. Some modern craft brewers use coolships to experiment with spontaneous fermentation in a variety of beer styles, seeking to capture unique local terroir in their brews.

Challenges

The use of coolships in brewing presents several challenges, including the risk of contamination by undesirable microorganisms and the difficulty in controlling the fermentation process. Brewers using coolships must carefully manage their brewing environment to encourage the growth of beneficial microbes while minimizing the risk of spoilage.

Conclusion

Coolships represent a bridge between the ancient art of brewing and modern brewing practices, embodying a tradition that has been preserved and adapted over centuries. They play a crucial role in the production of some of the world's most distinctive and cherished beers, allowing brewers to harness the power of nature in the creation of complex, flavorful brews.