Why care about yeast nutrition?
For the last five years, we have been working diligently at Escarpment Labs to answer these questions. What does yeast want? What does yeast need? While we started off with some pretty good guesses, the research and experience gained from many years of intensive propagation has yielded new insights and understanding of the unique nutrient requirements of our strains.
As with pretty much every story we tell about our yeasts, we find them to be distinct characters with their own wants and needs. Some of our yeasts respond really well to the right amount of vitamins. Some really need a bump of magnesium to perform well in high gravity fermentations. Some need a little bit of extra FAN to be their best yeasty selves.
Without sounding too much like a breakfast cereal commercial, we're going to dive into all the important vitamins and minerals needed for optimal yeast performance, and the solution we came up with for brewers.
This story started with a lot of liquid malt extract (our primary yeast food) which was producing below-average yields of many of our yeast strains, especially British strains such as Vermont and Foggy London. After much hair-pulling and data analysis to rule out process variables, FAN content, and water chemistry, we looked at the vitamins. We found this lot had below-typical concentrations of vitamins such as biotin and thiamine. Supplementing these vitamins returned the yields to normal, and this is when we learned that some yeasts have a higher need for these vitamins than others.
This was an important lesson to learn: brewer's wort is typically a good source of vitamins for yeast health, but sometimes wort can vary in vitamin concentration. When we're talking vitamins important for yeast, we're mostly talking what are known as the B vitamins.
Thiamine (Vitamin B1) is quickly consumed by yeast, and is known to improve yeast viability during and after fermentation. Riboflavin (Vitamin B2) is important for yeast since a key metabolic reaction, the Krebs cycle (remember high school biology?!) needs it as a cofactor. Biotin is important for fermentation of sugars as well as for other key enzyme pathways. Calcium Pantothenate (Vitamin B5) is also needed for key enzyme functions.
Inositol (or myo-inositol) is a direct component of phospholipids, the building blocks of the yeast cell membrane. This means it's important for yeasts to bud and make new yeasts, and to repair their own membranes.
|Vitamin||What it does|
|Thiamine (Vitamin B1)||Improves yeast viability|
|Riboflavin (Vitamin B2)||Metabolic reactions|
|Biotin||Sugar fermentation, key enzyme pathways|
|Calcium Pantothenate (Vitamin B5)||Key enzyme pathways|
|Inositol||Cell membrane creation and repair|
The amount of minerals needed for yeast is often quite small, but they play a big role in the development and metabolism in yeast cells.
Inorganic cations are also important to yeast performance. Manganese, calcium and zinc ions are all critical for yeast growth. Zinc in particular is only available in trace levels but is not replaceable by any other metal ion as it is essential for structure and function of key fermentation enzymes.
Magnesium ions are essential for yeast growth and division during
mitosis. Also, magnesium can exert a protective effect on yeast for high stress situations such as high gravity brewing. Trials at Escarpment (way back in 2016) showed that Vermont Ale performed better in high gravity brews when given supplementary Magnesium.
Phosphates are very important for yeast, since phosphate uptake is coupled with nitrogen uptake. As a result, if the wort is deficient in phosphates, then the yeast cell will have a harder time using nitrogen, resulting in poorer growth and performance.
Inorganic sulfur and chloride are also needed by the yeast cell for
amino acid production and transport mechanisms.
|Mineral||What it does|
|Calcium||Yeast growth and flocculation|
|Phosphates||Coupled with nitrogen uptake|
|Sulfates||Amino acid production|
|Chloride||Membrane transport mechanisms|
Oxygen is also very important for both fermentation and yeast growth, although wort fermentation is basically anaerobic. While it's tricky to supplement oxygen in a yeast nutrient, we think it is worth mentioning that oxygen should be considered a critical nutrient for beer fermentation performance. We will share some additional content on oxygen in beer in the future.
Our effort to learn about the nutritional needs of all of our yeasts led to the development of Yeast Lightning, which is our very own nutrient blend, optimized for beer yeasts. We think it will help brewers have a better success rate with fermentation, leading to less stressed yeast and therefore less stressed brewers.
Historically we have recommended nutrient blends from other sources but this always left us wanting - we knew that most of these products were formulated with wine yeasts in mind, and wine yeasts are not the same characters as beer yeasts. They have different needs and tolerances (for example, wine needs more FAN supplemented than wort).
Beer typically contains enough FAN, but addition of micronutrients such as vitamins and minerals can help beer yeasts perform at their best, every generation. That's why when we formulated Yeast Lightning, we reduced the concentration of FAN. Your wort probably has enough, and if it doesn't, it's going to be cheaper for you to supplement with straight up diammonium phosphate (DAP).
What your wort might not have enough of is fermentation-enhancing vitamins and minerals. In Yeast Lightning we've made sure to include extra biotin and thiamine, which we have found to be important to performance, especially in strains popular in hazy IPAs (e.g. Foggy London, Vermont, Hornindal Kveik). Magnesium makes a showing, which helps to improve ethanol tolerance in high gravity ferments. Zinc, being a critical cofactor needed by key fermentation enzymes to function, is present.
We did an experiment where we fermented wort with 5 different strains, and left it warm for 2 weeks, then checked the yeast viability. Under these non-ideal conditions, Yeast Lightning resulted in a viability boost, especially in the second generation of use.
Many nutrient blends formulated for wine yeasts contain copper sulfate. Copper can be useful as a yeast supplement, since copper can react with sulfide compounds and remove sulfury, farty aromas. However, many beer yeasts are much more sensitive to copper than wine yeasts, meaning that the concentrations typically found in nutrient blends geared toward wine yeasts can have potentially detrimental effects on beer yeasts. Moreover, excess copper is not something you want in wort as it has potential to accelerate and enhance staling reactions, making fresh beers oxidize faster. It's especially something you don't want to be adding to your hazy IPAs. Long story short, we kept copper sulfate out of Yeast Lightning.
For pro brewers, Yeast Lightning is available now. Recognizing the demand for great nutrients from home brewers, we are also working on a homebrew-sized format.