Mold
(In progress)
Mold is a type of fungus. It appears on surfaces as fuzzy or hairy patches and may be colored as white, gray, green, red, or black.
Wild mold growth is a health hazard because it can produce allergens and toxins, some of which are carcinogenic. Therefore if there is any mold growth on your batch, all of it should be dumped, carefully (to avoid spreading more spores).
The one exception to this is when a domesticated mold culture is used intentionally, such as with Sake, rice wine, or some cheeses.
Prevention
Mold can generally be prevented in beer by oxygen avoidance and pitching healthy yeast. In wine, pitching healthy yeast, punching down fruit, sulfite usage, and stabilization can all help prevent mold growth.
Reducing open air exposure goes a long way toward lessening mold spores and therefore reducing the risk of mold growth. To prevent mold growth while allowing oxygen exposure (such as needed for kombucha production), loosely covering the vessel with foil is a good option, or using an airlock with a HEPA filter.
See Contamination for more info.
Myths
Myth: The beverage will be OK if you just scrape off the mold patches.
Truth: Mold is by definition filamentous. It sends out hyphae, or "roots" in laymen's terms, and it can secrete allergens, toxins, and carcinogens that would be impossible to separate from the liquid/culture. Carcinogens wouldn't get you sick immediately, so you wouldn't even necessarily know you're ingesting them.
Myth: Small amounts of mold may be OK.
Truth: We generally recommend avoiding the health risk, as does the USDA:
"Microbiologists recommend against scooping out the mold and using the remaining [soft food]."[1]
It's impossible for us to quantify how much mycotoxin or allergens may be present. Some people have life-threatening reactions to penicillin for example, which could trigger with a very small amount.
There are a wide variety of possible mold toxins and they have negative health impacts even in small amounts.[2]
Home brewers have experienced serious illness from brewing with moldy grain.[3]
See also
References
- ↑ "Molds On Food: Are They Dangerous?" USDA Food Safety and Inspection Service, August 2013.
- ↑ "Mycotoxins." World Health Organization (WHO), May 2018.
- ↑ "Nothing that can hurt you can live in beer- Confirmed!" Forum thread, HomeBrewTalk, December 2019.