Chitosan in Brewing

Q. I have read a few things about the use of chitosan in beer and would like to get your input on this topic.
Kevin Sullivan • Spokane, Washington

Mr. Wizard says…

A. Until recently, I hadn’t paid much attention to chitosan because it was one of those finings that seemed more popular among winemakers than brewers. And the few chitosan products I knew about that were available commercially were made from shellfish, posing an allergen risk for consumers with shellfish allergies. That’s not to say other chitosan products haven’t been around for a long time — I was simply unaware of them.

Two things have recently opened my eyes to chitosan products: The search for alternatives to pasteurization for use in non-alcoholic beer and the growing market visibility of fungal (vegan) chitosan for use as a beer clarifier. Before digging into these applications, I want to briefly introduce chitosan to those who may not be familiar with it.

Chitosan is a naturally derived fining agent used to clarify beer (and wine) by helping unwanted haze-forming particles drop out of suspension. Although chitosan isn’t a protein, it behaves similarly to isinglass. It’s produced by deacetylating chitin, a structural polysaccharide found primarily in the shells of crustaceans like shrimp and crabs — but it can also be sourced from fungi. In fact, fungal cell walls, especially those of Aspergillus and Mucor — a genus of filamentous fungi found in soil, decaying organic matter, and even some fermented foods — provide an increasingly popular and sustainable non-animal source. 

Chemically, chitosan is a positively charged polymer and ranks as the second most abundant natural polysaccharide on Earth, right after cellulose. That abundance makes it both renewable and relatively inexpensive. When added to beer, chitosan’s positive charge acts like a magnet for negatively charged particles — proteins, yeast cells, tannins, and other haze formers. These bind together into heavier clumps that sink out of suspension, leaving the beer clear and bright. Chitosan works gently, without stripping flavor or aroma, and is often paired with silica-based finings for even better clarity and stability.

Although chitosan can effectively clarify beer on its own, it’s often paired with kieselsol — a colloidal silica better known by the trade name Biofine Clear. The name kieselsol comes from the German word for flint or silica — “Kiesel” — combined with “sol,” which refers to a specific type of colloidal solution. The two work synergistically because they carry opposite electrical charges: Chitosan is positively charged, while kieselsol is negatively charged. When used together, they act like a two-step magnetic system. Kieselsol first binds to haze-forming proteins and other positively charged particles, creating small flocculates. Chitosan is then added, binding to the remaining negatively charged yeast cells, tannins, and colloids. The result is a faster, more efficient precipitation of haze components than either agent can achieve alone. This pairing produces bright, shelf-stable beer without filtration — ideal for brewers who want professional clarity while maintaining full flavor integrity.

That’s the fining story about chitosan. A more recent development involves specific chitosan fractions being used for their antimicrobial properties. Chiber — short for Chitin-Based Extract for Beverages — is a new product gaining attention in the beverage and food industries for its ability to inhibit and prevent the growth of certain microorganisms.

Unlike heat pasteurization, Chiber is active immediately upon addition and continues to work through packaging, offering an advantage over flash pasteurization, where contamination during filling can lead to in-package spoilage. While larger breweries often use tunnel pasteurization to treat beer in the package, flash pasteurization — a lower-cost, inline process — is more common among craft brewers. However, the risk of contamination during canning, bottling, or kegging has many brewers exploring alternative methods to meet the growing demand for safe, shelf-stable, non-alcoholic and low-alcohol beers.

Chiber is already being tested by some brewers, but because it’s relatively new to the market, most are still trialing it and developing best practices. The feedback I’ve received from brewers who have used or are currently trialing Chiber is that more testing is needed. It may prove to be a great fit for simpler beverages like sodas but may or may not be the best option for beer.

And it’s not an off-the-shelf additive; testing is required to establish an appropriate process for each beverage type. A simple preliminary check involves confirming that Chiber does not cause sediment formation when added to the product. Because it’s a specific fraction of chitosan, Chiber can also act as a fining agent — so if the target beverage is unstable or prone to haze, the active antimicrobial ingredient may be reduced as it binds and settles out with other particles. Several brewers have told me that it simply doesn’t work with hazy beers because it causes clarification and is essentially neutralized in the process.

To our commercial readers who are interested in brewing non-alcoholics (NAs): Work with a process authority and conduct extensive third-party challenge testing to ensure your product is stable, regardless of the stabilization method used. And until we have more research data from multiple research groups, please don’t put NAs on draft.