In a nutshell, Urea is a chemical compound that can occur naturally or synthetically. Commonly used in fertilizers, animal feed, and diuretics, Urea itself is not dangerous. However, in fermentation, Urea is known to contribute to the production of ethyl carbamate, which is a carcinogen and has therefore been banned in beverage alcohol production in some countries.
The Great Safety Debate
There isn’t much of a debate over whether ethyl carbamate is safe: Ethyl carbamate (also known as Urethane) is a Grade 2 carcinogen that is known to produce cancer in primates. The debate lies in whether the amount of ethyl carbamate produced from Urea during fermentation is at dangerous levels after the distillation process is complete. In New Zealand and Australia, Urea was banned as a nutrient in 1984 only to have the ban later lifted in 1994, but the ban was reinstated a couple of years later and remains in effect today. Keep in mind that we are talking about the use of Urea in food-grade products, which is different from its use in other types of products such as fertilizers. In 2005, the US National Library of Medicine National Institutes of Health published a report on the safety of Urea that claimed the use of Urea safe “to facilitate fermentation of wine.” However, it is not safe for use in distilled spirits due to the bigger issue caused by the elevated temperatures that occur during distilling. Plus, most wineries even continue to choose to use methods to avoid using Urea during fermentation, with many even trying to avoid using fertilizers with Urea on their grapes.
The Technical Side
The reality is that studies conducted on the risk of cancer from ethyl carbamate in alcoholic beverages have shown that ethyl carbamate does pose a significant risk for the alcohol-drinking population (just Google “ethyl carbamate in alcoholic beverages cancer” for more information on various studies). Technically speaking, the recommended limit for ethyl carbamate is 125 parts per billion (ppb). In the 2000s, an agency that tested widely marketed distilled spirits found that most bourbons contained several hundred ppb, that plum and cherry brandies varied from 200 to 12,000 ppb, that dessert wines varied from less than 4 ppb to several hundred ppb, and that table wines had 0 to 25 ppb. Since then, bourbon manufacturers have found that they could lower the levels of ethyl carbamate by modifying the distillation process.
Is There Urea In My Turbo Yeast?
If Urea is an additive in your turbo yeast, it may not say so right on the package. However, turbo yeasts that do NOT contain Urea will specifically say “Urea-Free” or “Does not contain Urea” on the package. This was a tough topic for me to get to the bottom of because there has been so much back-and-forth over the years. It’s considered safe one year, then it’s not safe the next, then oh wait it’s safe again, etc. From what I can gather, the latest evidence shows that it can in fact increase your risk of cancer and it is not recommended to use turbo yeasts that contain Urea due to these safety considerations.
Feel free to research this topic yourself and draw your own conclusion. I’m aware that some people choose turbo yeasts with Urea because they ferment just a bit more thoroughly regardless of the known health warnings. It’s entirely up to you whether you want to use turbo yeast that contains Urea or turbo yeast that does not—you have both options available to you. I personally choose Urea-free turbo yeasts over those with Urea because I’m aware of the health implications, but to each his own. Oh, and also because Urea is essentially the waste produced by land-based animals: That’s right, Urea is what's in urine, and I have no desire to ferment that!