Matcha Froth
Foam, Forth, Crema…
That mysterious cloud-like layer made by vigorous whisking, and one of the standards for a five star matcha review. It is often said that it takes years of practice to master the art of matcha frothing. I am no whisking master, but after experimenting with a few matcha blends, foamability clearly varies from blend to blend. The ideal froth is uniform with small bubbles and forms an even layer across the entire matcha surface. When you know your crema, you will also know the background of your matcha powder.
Saponins
One of the main agents contributing to matcha foamability is saponin, a compound naturally found in various plants. The tea plant is low in saponins, especially compared to plants in the legume family. If you’re vegan, you may have used aquafaba (water from a can of chickpeas) to bake meringues or other desserts. Due to its high content of saponins, aquafaba forms stiff peaks within minutes of whisking. Matcha powder possesses just enough saponins to create a light surface froth. Saponin is part of the plant’s immune system and is stimulated by stress. Shading green tea plants creates a healthy type of stress that helps the plants develop flavor, caffeine, and saponins, leading to greater foamability.
There are two factors that help activate saponins during whisking; temperature and pH levels. Studies show that a rise in water temperature can increase saponin concentration and solubility. In other words, warmer water will produce more stable froth than a cold brew method. Higher pH levels also increase foamability. Most matcha ranges between a 7 - 10 pH level. Cultivation methods have the highest impact on exact pH levels. The better the shading, the more chlorophyll will the plant produce, which in turn raises the pH. A fine matcha is derived from well shaded tea plants, and therefore has a higher pH and should produce nice foam when whisked.
Amino Acids
Research on sparkling wine tells us that arginine, asparagine, and tyrosine amino acids help stabilize foam. These types of amino acids are also present in matcha, but in fairly low quantities. A well shaded and fertilized tea plant will produce higher quantities of various amino acids, which will also contribute to a frothier matcha.
Tools
Matcha foam is both a product of chemical composition and the tools used for whisking. Whisking aerates the powder, resulting in a more flavorful matcha latte. Using a wide bowl will allow for better whisking techniques. Believe it or not, using a small bowl or skipping whisking will actually result in a monotone or dull tasting matcha. Whisk size, shape, and material can all have an effect on frothiness. Bamboo whisks are regarded as the best for whisking because they do not alter matcha flavor and are gentle on the delicate powder. There are many different types of bamboo whisks intended for different types of tea ceremonies. Research found that Yabunouchi bamboo whisks show the best results for uniform foam, but both Kankyuan and the more commonly used Ensyu whisk can also produce lovely results. In the West, these names are often absent from labels, so instead look for a whisk with a high prong count (80 or higher).
All these components come together and interact to create matcha foam and affect its stability over time. Cultivation is where it all begins, but there are a few things we as consumers can manipulate for better frothing. Bellow is my experiment observing the effects of water temperature, powder to water ratio, and whisking time on froth quality. Results reveal that powder to water ratio and whisking time have the greatest impact on how frothy matcha gets. My particular results show that using 3 scoops of matcha and whisking for 60+ seconds produces the best froth. Water temperature had less of an effect on foam than the other variables. And yes, this experiment required making 9 different matchas in one day. It was a very happy day.
