Top 10 Reasons For Fermentation Failure
By Ed Kraus
Lack Of Nutrients:
Having sufficient nutrients in a must is an integral part of any successful wine fermentation. Without nutrients the wine yeast is unable to perform to its fullest ability. The result is a wine fermentation that is sluggish and quite often, one that will stop altogether--before the fermentation is complete.
The typical nutrient-deficient fermentation will usually struggle along with some success for the first few days and then seemingly hit a brick wall, ceasing all but an insignificant amount of activity. This scenario occurs primarily because the wine yeast is able to consume the simplest sugars that are available without much nutritional need. But as the simple sugars are used up and the preserving effects of alcohol starts to increase, the wine yeast cells end up simply "meeting their match".
Another reason the wine yeast will stop in mid-fermentation, is that the little amount of nutrients that were available to the wine yeast are now gone. The wine yeast actually consumes them, leaving the must that was just short on nutrients, now with next to no nutrients at all.
When making wine from grape juice, either fresh or packaged, nutritional needs are easily met by simply adding what is known to home winemakers as "Yeast Nutrient" or "DAP" which stand for Di-Ammonium Phosphate.
There are two reasons why nutritional needs are fully met so easily when fermenting wine from grapes. The first being that wine yeast are specifically developed with grape juice in mind. The various strains of wine yeast are actually developed in a grape juice environment so as to acclimate them to grape juice. The result is wine yeast strains that are very happy with the set of nutrients that grape juices typically provide.
The second reason is that when making with grape juice, very seldom is the juice diluted with water. So the nutrients from the grape juice are at full strength as well. Even when making wines from concentrated grape juices, this holds true. The concentrates when diluted back to their original volume, contain a same wealth of nutrition as they did before being processed.
The only thing you can really do to improve the set of nutrients in these grape juices is to add "Yeast Nutrient," as mentioned earlier. This product adds both nitrogen and phosphorus to a fermentation. You can kind of think of it as adding fertilizer to your wine yeast.
Unfortunately, when making wines with most other fruits the plot thickens a little. When making wines from berries, plums and the like, having ample nutrition in the right balance for the wine yeast is a significant issue that needs to be addressed.
With these types of wines, the nutrients that are naturally provided by the fruit may not be of the balance or type that wine yeast needs to perform to their maximum ability. Also with these wines, the juice almost always needs to be diluted significantly with water and sugar. This in turn dilutes the various vitamins, proteins and minerals as well.
When making these types of wines a more well rounded set of nutrients is required. One that not only provides more nitrogen and phosphorus in a simple form such as our Yeast Nutrient, but one that also provides proteins, minerals and vitamins in a proper balance. Such is the case with "Yeast Energizer."
Yeast Energizer is designed specifically for nutritionally aiding the fermentation of everything from berries to bananas. It contains a blend of nutrients that helps to fill the nutritional voids that some recipes can create.
One way to know if Yeast Energizer is needed in a wine you are making is by giving it a simple test. Ask yourself, "how close is the produce I am using to a grape?" The closer the produce is to a grape, the less likely you will need to use Yeast Energizer. For example, a currant wine is much less likely to require Yeast Energizer than say, watermelon wine.
Another way to know is by simply following a recipe. Most recipes will indicate if "Yeast Nutrient" or "Yeast Energizer" is required. There really is no reason to second guess a wine recipe that indicates a specific type of nutrient. Just the fact that the wine recipe calls for a nutrient of any kind, usually means that it is probably from a sound source.
As a final note, there are some produces that put a tremendous strain on the yeasts' ability to ferment. Some of these would be things like honey, dandelions and vegetables. With these types of produces, nutrients may be plentiful, but they are not of the kind wine yeast need. When fermenting these types of musts, we recommend not only using Yeast Energizer, but also using something called "Ghostex" along with it. Ghostex enhances the yeasts' ability to multiply itself. This gives the yeast a fighting edge when it comes to completing a fermentation.
- To read a little more about wine making nutrients, see the following article listed on our web site: "A Few Words About Nutrients"
- For more information about the nutrients we offer, go to: Wine Making Nutrients
Ed Kraus is a 3rd generation home brewer/winemaker and has been an owner of E. C. Kraus since 1999. He has been helping individuals make better wine and beer for over 25 years.