Finding clarity in beer. Craft Beer & Brewing reviews kettle finings and the benefits of carrageenan in the brewing process.
In a recent Web-exclusive article on beerandbrewing.com, I addressed a few of the reasons that you might turn out a hazy brew here and there. One of the culprits I mentioned was chill haze, a mostly harmless condition in which proteins and tannins huddle together in the cold and obscure your pint. Maintaining a healthy, rolling boil, followed by rapid cooling can help reduce haze, but a complementary approach is to use a fining agent.
Finings are added to wort or beer to promote clarity in the finished product, and there are two broad classes. Kettle finings are added while wort continues to boil away in the kettle, whereas fermentor finings are added to finished beer. We’ll focus on kettle finings for now and discuss fermentor finings next week.
Kettle finings are almost always made from Chondrus crispus, more commonly called Irish moss, a red seaweed that contains a great deal of carrageenan. Carrageenan, in turn is a type of polysaccharide (carbohydrate) that is widely used in the food industry as a thickener. Many vegan products make use of the carrageenan in Irish moss as a non-animal alternative to gelatin. Even affirmatively non-vegan products such as yogurt and ice cream often include carrageenan as an inexpensive thickener.
So what does this have to do with clear beer? Well, as it happens, carrageenan carries a fairly strong negative charge and is all too eager to bond with positively charged proteins floating around in wort. When carrageenan is introduced into boiling wort, it matches up with said positive proteins and, upon cooling, forms large clumps that precipitate out of suspension and fall to the bottom of the kettle.
Read more from the source: Craft Beer & Brewing Magazine