Using Yeast Energizer

[Fitz]

In Jack Keller’s blueberry wine recipe he used “split” yeast energizer. 1/2 after adding the yeast and then the other half after SG drops to 1.060. I’m only familiar with using it for stuck fermentation. Can someone explain why he used it this way? And how one might consider using a split yeast energizer when developing a recipe? Thanks in advance.

 

[Rice_Guy]

The recipe for yeast energizer probably is referring to what most of us are calling nutrient. Organic nitrogen (Fermaid O) or the older DAP. With these forms of nitrogen it is typical to add a dose at start of fermentation and a second dose at 1/3 sugar reduction, nominally 1.050 to 1.060. Some of the mead recipes I have seen will use smaller additions as at 1.090, 1.070 and 1.060.
Why? Having smaller additions keeps the yeast from going wild, excessive heat buildup, crashing, having a high population. This is thought to be better on the flavor.

 

[Fitz]

In Jack’s recipe, he also used yeast nutrient as well as yeast energizer. The recipe that I’m referring to is in his book (In case you have or seen one.)

 

[Rice_Guy]

Haven’t read Jack’s book, only picked out specific recipes.
The logic again would have to be follow the growth curve. The micro nutrients (vitamins, magnesium, hulls, etc) would be supplying limiting factors for yeast growth. This would be similar to providing vitamins in our diet, we don’t manufacture them so need em in foods.
Good question! I am going to look more at this, and may make it standard procedure.