Hobby wine and beer makers know that yeast used for brewing needs to be fed, so it can grow and carry out the process of fermentation. After all, yeast is a living organism. While some fruits, flowers and vegetables contain some of the nutrients that yeast needs, using a yeast nutrient like Tonozymol can ensure that your yeast gets a good balance of vitamins and minerals.
Many yeast nutrients are on the market, and they all work pretty much in the same ways, notes winemaking enthusiast Jack B. Keller on his website. One of the nutrients that is naturally lacking in most wines is nitrogen, notes the E.C. Kraus website. Making sure yeast has enough nitrogen can help it reproduce more easily and produce higher levels of natural enzymes that result in faster ageing. Yeast nutrient provides nitrogen in the form of phosphate. In addition, yeast nutrients commonly contain trace minerals and vitamins.
Ritchie, the manufacturer of Tronozymol, states on its website that this is the best-selling yeast nutrient in the United Kingdom. It's "ideal for four-week wine production and preventing stuck fermentation," the site states. It also notes that Tronozymol comes in three sizes, 5gm, 100gm and 200gm.
All musts that are not grape-based, like those used to make beer, may benefit from one teaspoon of yeast nutrient such as Tronozymol per gallon of liquid, according to Keller. The nutrient should be added in the early stages of fermentation, when you most need the yeast to be active.
Malt extract and lemon juice make for a decent nutrient if a nutrient like Tronozymol is unavailable, according to Keller. However, Tronozymol can be purchased cheaply through a wide variety of web sites.
While Tronozymol is supposed to prevent a "stuck" yeast, a yeast energizer may be more beneficial than a nutrient if your yeast has already become stuck or slowed its pace of fermentation. Like a nutrient, an energizer provides the yeast with nutrient, but from a larger range of substances than just phosphate, notes the E.C. Kraus site. Energizers also contain yeast, more than a dozen yeast extractive proteins and B1 vitamin, which are sources of nitrogen. Energizer, instead of nutrient, should be used when fermenting meads, vegetables and herbs, which are completely unlike grapes, according to E.C. Kraus. That's because these types of musts usually lack the nutrients that wine yeasts receive, and yeast energizers can compensate for those deficiencies.