Yeast nutrient DAP a.k.a. Di-ammonium phosphate is a Nutrient Blend with some vitamins, zinc, and micronutrients. Each gram of yeast nutrient blend provides the ~205mg of YAN needed for the yeast. YAN or Yeast Assimilable Nitrogen, needed for it to multiply and prevent stuck fermentation. DAP is multivitamins for the yeast to create strong cultures. We can also use yeast nutrients as yeast energizers during stuck fermentation. It is good to stop the yeast from mutilating in a stressed environment – high sugar, low pH, low temperature, zero oxygen, etc.
Dosage for Yeast Nutrient
For Yeast Nutrient DAP: Use between 0.25gm to 1gm per liter. Do note that higher sugar (or alcohol levels) and low O2 levels stress the yeast. So higher is your Brix/ Degree Plato values, the more nutrients you need to add. If you are step-feeding sugar in your wines, please add nutrients also in each step.
For grain mash 0.25gm per liter added along with yeast starter gives the best results.
Also recommended to be used along with stir plates if you are washing/propagating yeasts and other wild cultures. Agar & petri-dish can be obtained from the medical labs.
TTB (American Alcohol & Tobacco Tax & Trade Bureau) limits yeast nutrients to 0.968 g/l, which is enough to give the YAN (yeast assimilable nitrogen) to give 15% v/v strength of ethanol.
Benefits for using Nutrient Blends
Removes the sulfur smell from fermenting (which is usually because of stressed yeasts).
Improves the Alcohol ABV by helping yeast finish fermenting dry.
Accelerates the fermentation rates especially for brewers of winters and Himalaya regions.
Winemaking is like any fermentation or curd making. If you add too much jaman (curd starter culture), then your milk will turn into curd faster, but there will be no other perceivable change in your final product. However, if you don’t add enough starter culture, then the milk will spoil. Similarly, wines require a dosage of yeast. If the active yeast cell count is too low, you will be prone to spoilage. However, adding too much yeast will only lead to faster fermentation and no other change. The yeast will finish their job fast, settle at the bottom, and will be raked off.
Adding too much yeast nutrients or DAP is serious. It is a chemical and usage of more than 1gm per liter is banned in the USA.
Typically 4-12 days but it depends on a lot of factors:
Fermentation temperature. Higher the temperature faster the fermentation is (but beware of the off-flavors produced in yeast fermented at above 25 degrees Celsius)
Yeast dosage. although 1gm/liter is recommended. Increasing it to 3gm/liter can produce wine in 2-3 days (50% reduction in time)
Availability of yeast nutrients. Grape and fruit juices don’t have enough natural proteins for the yeast to multiply fast. Adding 0.5-1gm per liter of yeast nutrient is sufficient to establish a healthy yeast colony and fast fermentation. Mead is notorious for being slow to ferment and produce nail polish like off-notes because of a lack of nutrients.
Sugar concentration: 18-25% w/v of sugar concentration is ideal for fermenting with wine yeast. However higher the concentration, the more time it will take for the yeast to finish its job and produce ethanol.
Raisins are dried grapes. If grapes had enough ammonia, phosphorus, zinc, and vitamin Bs then we would not be adding nutrients in the first place. So short answer is that raisins are a good source of glucose and cellulose (skin). It is not a good source of nutrients. The raisins do help in improving the flavor and ABV of your homebrew, but apart from that, it has little impact on the health of your yeast colony.
Yes, you can ferment homebrew wine and beer without yeast nutrient as well. However, it helps because of the following reasons:
yeast nutrients have YAN (yeast assimilable nitrogen) which is needed to establish a healthy yeast colony. Healthy yeast = faster fermentation, lesser chances of infection (which means safer ethanol production), lesser yeast mutation (better flavor consistency).
It prevents stuck fermentation
Better flavor profile. Nutrients reduce the stress on yeast and prevent the off-flavor production in homebrew beer and wine
Yeast is very temperamental and goes bad very fast. In comparison, yeast nutrients are chemicals and dead yeast extracts that have a 2-5 year shelf life. So it is completely fine to use an old yeast nutrient in your yeast starter.
If you happen to stumble upon an old yeast nutrient and cannot buy a replacement, then don’t worry.
Take 100ml of water
Add 5gm of sugar
Add 5 gm of yeast nutrient (old)
Boil the three for 10 minutes and cool it in an ice bath
Wait until the temperature reaches 30 degrees
Sprinkle 5gm of dry yeast, stir gently and wait for 15-60 minutes
Whoa! you have a yeast starter for a 10-liter batch.
Yes, they need lots of yeast nutrients (0.5-1gm per liter compared to 0.25gm per liter in case of homebrew beer). The reason is that honey and apple/fruit juice don’t have enough proteins and nitrogen. With a low YAN (simply put nitrogen that yeast can use) the fermentation tends to get stuck and is prone to infection. To compensate that we use 2-4 times more yeast nutrient. This helps establish a healthy yeast colony, prevent infection, stuck fermentation and off-flavors
Yeast is the single-celled microorganisms that are responsible for fermenting sugar (maltose, glucose, fructose, sucrose, etc.) to ethanol. In the absence of oxygen, these yeasts do the transformation which converts your grain/fruit into a beverage. Yeast nutrients, on the other hand, are food for the yeast. On their own nutrients achieve nothing more than making a comfortable home for the yeast to function at its best capacity. Yeast energizer, on the other hand, is an SOS remedy needed to recover from stuck fermentation or incomplete fermentation or excessively low-temperature fermentation which can make yeast sluggish.
Although Yeast Energizers are types of nutrient blends, they also contain components such as vitamin B, diammonium phosphate, tricalcium phosphate, magnesium sulfate, and yeast hulls. Yeast energizers are particularly useful to restart a Stuck Fermentation, as it allows yeast populations to increase in a batch of beer or wine which likely has been depleted of these components due to an earlier yeast population growth. The additional components included in Yeast Energizers are most effective when for high gravity fermentation (high sugar high alcohol), low-temperature lagering, excessively low pH, high ash content (molasses) and other extreme fermentation styles.
The best time to add yeast nutrients is in the starter culture when you are hydrating the yeast. Beer brewers also add yeast nutrients during the last 10 minutes of the boil so that the ingredient gets sterilized. Wine and cider makers typically add it during step feeding (along with sugar in 2-3 stages during the initial days of fermentation). What you should never do is add the yeast nutrient along with Camden (potassium metabisulfite) on the first day i.e. before adding yeast. This is food for the yeast and not for other bacteria and wild microorganisms. Similarly, whether you are making beer or wine, don’t add it in second or after 3 days into fermentation (unless it is a stuck ferment)
Yeast Nutrient & Energizer will remain stable for 1 year if stored in an airtight container in a cool environment away from sunlight. Simply reseal the silver pouch and keep it in the refrigerator/freezer and you should be good to go.