During the production of cow’s milk products, large amounts of by-products are often generated. These include, for example, buttermilk in butter production and whey in cheese production. For a long time, these by-products were mainly used as animal feed and hardly utilized in food or otherwise. But is that still the case today?
What classic by-products are generated in a dairy and what do they consist of?
When the liquid separates from the solid part of the milk, one might think that the liquid consists only of water. However, since buttermilk and whey still contain many valuable components of milk, attempts are made to utilize them sensibly. But how much whey and buttermilk are actually produced? The amount of buttermilk produced during butter production depends on the fat content of the cream used. If whipping cream with about 30% fat is used, approximately 300 to 400 ml of buttermilk are produced when making around 250 g of butter (Image 6A). The amount of whey produced also cannot be stated generally. It depends primarily on the type of cheese produced. However, about 2.25 l of whey are produced when making 250 g of semi-hard cheese (Image 6B). This example shows that whey, in particular, is produced in large quantities. Therefore, there are already many clever ideas for its sensible use.
Experiment: Making Butter
How are the by-products already being further utilized?
The simplest way to use whey and buttermilk is to sell them as a drink (Image 7). To make the sour taste more pleasant, they are often mixed with fruits. However, there is a problem, especially with whey: the large quantities produced during cheese production cannot be consumed solely as a drink. Therefore, a popular method is to process the whey into whey powder (Image 7). Whey consists of about 94% water and about 6% solids, such as protein, milk sugar, and minerals. In the production of whey powder, the water is removed, leaving only the solid components. Whey powder has a big advantage: it is much more durable than fresh whey and requires less storage space. It can also be used in numerous foods as a substitute for milk. The powder can be mixed with different amounts of water. This prevents too much liquid from diluting the product. But whey offers even more possibilities. Before it is dried, experts often first extract individual valuable substances from it. These substances can then be used specifically for certain products and often sold at a higher price. A particularly well-known example is whey proteins (Image 7). They are especially popular in the fitness sector. The liquid that remains after the whey proteins have been removed is called permeate (Image 7). But permeate is also still useful. Lactose can be extracted from it (Image 7). This is used, for example, in foods or baby food. After the lactose has been extracted, a liquid remains again. This is called mother liquor (Image 7). Whey can also be used in another way. Some of its minerals can be removed. The whey is then called demineralized whey (Image 7). It can be used, for example, as food for sick people. This produces a salt solution (Image 7) as a by-product. However, there are only a few further applications for this salt solution. Many products that arise during the processing of whey are subsequently dried to make them more durable. This produces various powders. Drying also produces something else: whey condensate (Image 7). This is water that is formed during evaporation and is later condensed back into liquid. This water still contains milk residues. Therefore, it cannot simply be discharged into the drain. It must be purified first. But are whey condensate and the salt solution then the only by-products that remain?
What remains of the whey?
Even though there are many ways to use whey today, residues still remain. This is because not all products are equally popular. By-products, in particular, are often in less demand than the main products. Whey proteins are particularly popular in the fitness sector. Permeate, on the other hand, is used by only a few people. Therefore, more permeate often remains than is sold. Even if lactose is extracted from the permeate, the remaining mother liquor is not fully utilized. Furthermore, not all dairies produce all products. Therefore, not all possibilities for further processing whey are always utilized. This shows: although whey is a valuable raw material and versatile, components still remain. New uses must be found for these parts in order to utilize all substances completely and in their most valuable form. But is it actually sensible to utilize all substances to the end? This is precisely what the consideration of sustainability in economic production processes deals with.
How does whey become a sustainable food?
Infinite Roots and the Institute for Biocatalysis are researching this from 2025 to 2027 – they use whey as a nutrient for fungal mycelium and are developing a new food – also on Kniffelix.de from 2027!