What are Finings?
Finings are processing aids used to clarify beverages including beer, wine and non-alcoholic fruit-based beverages. Clarity is a desired quality for many beer styles, including most lagers and cask ales, where fining techniques are required to remove protein and yeast haze. Other beer styles like hazy IPAs are intentionally cloudy, as they rely heavily on the addition of protein-rich grains like wheat and flaked oats for a softer mouthfeel. While most beer will clear naturally over time, fining agents are typically added to accelerate the process.
Seeing Through the Haze
The haze in beer is from particulate largely comprised of leftover proteins bonded with polyphenols (a class of bittering/astringent compounds) naturally derived from malt and hops. Excess active yeast cells can also bond with these particles, but yeast is generally not the primary culprit for unwanted cloudiness in finished beers. A haze occurs when very small charged particles are suspended in a liquid, due to an electrostatic charge that repels one particle from another, hindering the settlement of the solid particles from the liquid phase.
Most finings used in beer are electrostatic, their naturally-occurring positive electric charge attracts negatively charged particles to them. The finings and their particulate form a larger neutrally-charged gelatinous mass that breaks colloidal suspension, resulting in a clearer beer.
Kettle Finings
Finings can be added at various stages of the brewing process to help achieve the desired level of clarity. Kettle finings, most commonly Irish moss and Whirlfloc, are typically added during the boil to help settle the proteins naturally present in grains such as barley, wheat and oats.
Irish Moss is red seaweed that contains carrageenan, a thickening agent, which binds to proteins and polysaccharides, causing them to precipitate out of the liquid. This layer of sediment remains in the brew kettle/whirlpool and not transferred to the fermenter. Whirlfloc is a tablet made by extracting purified carrageenan powder from Irish Moss. It is used in much the same way, but is more efficient due to its more potent formulation.
Cask Conditioning
Cask ales undergo secondary fermentation in the serving vessel, creating carbon dioxide that will naturally stir up any particulate matter. Finings are typically added directly to the cask during the final production stages to ensure it retains its clarity.
Isinglass is a collagen extracted from the swim bladders of fish, often used as a fining material for cask ales. Historically derived from sturgeon, isinglass today is typically acquired from farmed tropical fish. The collagen in isinglass is a triple charged helical coil, with several sites of positive charge, effectively forming a mesh-like structure that attracts negatively charged particulate to form a new larger particle. Once finished, the leftover particulate will form into a gelatin-like substance that settles out of the beer. As a fining agent, isinglass has the unique ability to settle particulate matter quickly and can do so repeatedly.
Beer brewed with isinglass is not vegetarian, though the level of isinglass remaining in an individually packaged product falls below levels of quantification. The amount of isinglass remaining in a cask is also quite minimal. That said, there are many diverse options available for fining beer, and many breweries are opting to use plant-based alternatives, such as Agar, Irish moss and vegan silica gels.
(Leah is a Toronto based freelance writer as well as the Beer Boss and a server at C’est What)