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.

 

[winemaker81]

I haven't used energiser in decades. Supposedly it's a different nutrient blend to give the yeast a boost.

Unless you have a specific problem, you can follow the package directions for whatever nutrient brand you have. It makes sense to split the dosage with 2/3 up front and the remaining 1/3 at 1/3 sugar depletion.

 

[winemaker81]

To clarify my last post, ignore the nutrient directions in the recipe and follow nutrient package directions, possibly with tweaks. *

Jacks recipes were recorded long, long ago ... in the distant lands of the 80's and 90's, and maybe earlier. Some appear to be copies of recipes from the 70's or earlier.

Until the last 15-20 years, there was (more or less) just "yeast nutrient" and "yeast energizer". Plain label, just one choice. I owned a LHBS circa 1990, and there were not a lot of choices in most things.

So ... recipes were based upon what was available at the time, and we can't assume the original author really knew what they were dealing with.

* regarding "tweaks", I typically follow package directions except for yeast strains with high nutrient requirements. Most yeast charts indicate if a strain is low, medium, or high nutrient requirements. I've had brushes with H2S in recent years, which is caused by yeast stressed because of lack of nutrients. So I bump up the nutrient to avoid the problem.