Kosher Whey – Yes Whey!

Whey protein concentrate supplements and whey-fortified products are among the most popular modern-day consumer health products. Whey-enriched shakes, bars, powders and pills flood the aisles of health food shops and online food marketing.

The demand for kosher whey products is immense, yet many whey products are not kosher-certified. Why is this? What needs to be done to get on board with kosher whey production?

Whey, which is the second most preponderant protein in milk (milk’s populous and massive casein protein comes first), is typically derived from milk via the cheese-making process. When milk coagulates into cheese, the fluid that remains behind is called liquid whey. Liquid whey is loaded with whey protein, which can be concentrated out; when concentration is performed at higher levels, the resultant product is called whey protein isolate. Whey protein isolate is about 92% protein, in contrast with whey protein concentrate, which is about 80% protein.

Although whey is a milk-based item, and it is not cheese (which requires a very specialized type of kosher production), it is not free of kosher issues. In fact, there are three main steps that must be fulfilled in order for whey to be kosher:


All ingredients in the cheese vat, from which whey is drawn, must be kosher. This means that all cultures, rennet, lipase, vinegar, nonfat dry milk and cream – whatever is in the vat – needs to be kosher-approved. This is the easiest part of kosher whey production, as these cheese-making ingredients are readily available as kosher.


This is where things can get a bit sticky – or a bit heated (sorry for the pun!). Cheeses manufactured at very high vat temperatures, such as traditional Parmesan and Swiss, usually cannot have their whey kosher-certified. The discussion revolves around a very technical issue in kosher regulations, but it is rare to come across kosher Parmesan or Swiss cheese whey. (Some companies have developed lower vat temperature methods for otherwise high temperature cheeses, enabling the resultant whey to actually become kosher-certified.) For the same reason, cheeses that are sprayed with very hot water toward the end of coagulation, while some whey is still in the vat, present a kosher issue regarding their whey, which thereby has high-temperature vat heat exposure.

Pasta Filata

Mozzarella and many other Italian cheeses are further hot-processed after formation. These cheeses are cooked, stretched and molded, in order to be endowed with an elastic texture, making them ideal for melting on to pizza or pasta. This cooking/stretching/molding regimen, known as the pasta filata process, starts in a large vessel (a cheese cooker) that is filled with very hot water. The water from cheese cookers is considered non-kosher – unless the cheese was made with special on-site rabbinical supervision. Some cheese plants opt to mix this non-kosher cheese cooker water with their whey, causing… you guessed it… the whey to become non-kosher. Pasta filata plants need to dispose of their cooker water in order to merit kosher certification, and any equipment used to handle pasta filata water cannot be shared with whey processing.

Thus, kosher whey involves using only kosher ingredients, cheese vat temperatures that are not very high, and an absence of pasta filata water in kosher equipment for whey processing.  

Once whey has passed the above hurdles and is deemed kosher, it can be pasteurized, concentrated, spray dried and further processed without issue, so long as the relevant equipment is kosher. When these kosher procedures have been successfully completed, all whey cream, lactose and whey permeate derived from the whey are likewise kosher.   

The OU is proud to certify dozens of whey and whey byproduct manufacturers in the United States and around the globe, as well as hundreds of the world’s most popular whey supplements and whey fortified products.

It’s time to say, “Yes whey!”