As the demand for plant-based milk alternatives continues to rise, coffee enthusiasts and baristas alike are exploring the science behind foaming these non-dairy options. While traditional dairy milk has long been the gold standard for creating the perfect microfoam for latte art, plant-based alternatives such as soy, almond, oat, and coconut milk present unique challenges and opportunities.
The Science of Steaming Milk
Understanding why dairy milk foams so well is crucial to grasping the challenges faced with alternatives. Dairy milk is a homogenized mixture of water, fat, protein, carbohydrates, and minerals. The interaction of these components during steaming creates the ideal microfoam. The fat content in milk determines the richness and thickness of the foam, while proteins stabilize it. As milk heats, caseins form a protective shield around air bubbles, creating a dense and sweet microfoam.
Challenges with Non-Dairy Alternatives
Non-dairy milks, being plant-based emulsions, behave differently when steamed. They often contain varying levels of proteins and fats, making them more heat-sensitive. For instance, soy milk proteins can denature and curdle at high temperatures, while almond milk can produce a thinner microfoam with a potential bitter aftertaste. Oat milk, however, is favored for its ability to create a rich microfoam similar to whole milk.
Recipe Variability and Its Impact
One of the significant challenges with milk alternatives is the variability in recipes and formulations. Companies may change their recipes without notice, leading to inconsistencies in how the milk foams. Additionally, different batches of the same brand can behave differently due to slight variations in ingredients or processing methods. This unpredictability can be frustrating for baristas aiming for consistent quality in their coffee creations.
Firsthand experience
At Subminimal, we found the best local alternative milk for our tests during development was Oatside. Oatside gave us excellent and consistent results, but one day, the foam started falling flat, and we could no longer get good microfoam. We bought more, used a lot of it, and eventually contacted the company to explain the situation. We were using the same setup, but getting different results. They took us seriously and offered to pick up some of our cartons for analysis. Two months later, everything returned to normal, and we happily began microfoaming again. We concluded that this was due to a recipe change or an issue with a production batch.
Two years later, we suddenly heard from multiple customers in one area that their Oatside was no longer foaming and asking us what to do. Clearly, there has been a change again (hopefully temporary) that is preventing them from getting the best results.
The lesson here is that milk alternatives are recipe-based man-made creations, and the companies can adjust their recipes at will or have batches that behave differently from others.
The importance of freshness
It is also essential to use fresh milk-alternatives for the best result. A carton that has been open in the fridge for weeks won't foam quite as well as a freshly opened one. This is because the freshness of the milk-alternative plays a crucial role in achieving the desired texture and consistency. When a carton has been sitting in the refrigerator for an extended period, the quality of the milk-alternative can deteriorate, leading to subpar results. Therefore, for optimal foaming and to ensure the best possible outcome, it is highly recommended to use a milk-alternative that has been recently opened.
Innovations in Alternative Milks
To address these challenges, some companies are developing "barista edition" non-dairy milks with added stabilizers, fats, and sugars to mimic the qualities of dairy milk. These formulations aim to provide a more consistent foaming experience, allowing baristas to create high-quality microfoam for latte art.
Conclusion
Always use a "Barista Edition" milk alternative for the best results and be aware of its freshness. Sudden, unexpected changes in foaming behavior could indicate a change in the recipe or a problem with a production batch.