Questions about staggered nutrient addition

I've been hearing a lot about the staggered nutrient addition method and I had a couple questions. First, when is the fermentation midpoint? I looked around and all I could find was the formula (OG+TG)/2 but I don't know what the TG refers to. How do I find it? Second, I've heard that in most cases the faster something ferments the longer it takes to age. Does that apply when using this method?

TG is target gravity, so its whatever you want your final gravity to be is your tg.

the second question, i have no idea.

How do I find the target gravity? Is it guess work, or is there another way to calculate it?

Target gravity is however high you want it to be when it finishes. Higher the FG, the sweeter it'll be. TG is whatever you want it to be.

solusveritas said:

How do I find the target gravity? Is it guess work, or is there another way to calculate it?

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I think you're pretty close with this statement...perhaps it's not fully a guess, but it's at best an estimate. If your yeast has the alcohol tolerance to fully dry out your mead, then the FG is probably about 1.000 (in reality many meads go slightly lower; ie, 0.995-0.999).

If you're starting at an OG where your yeast potentially won't be able to fully ferment out before reaching alcohol tolerance, you might need to play with an ABV calculator to estimate what the residual gravity would be at that point.

Still, the actual alcohol tolerance of a yeast is highly variable, and has a lot to do with the make up of your must and other environmental variables.

I'd venture to say unless you have a good number of batches under your belt, and even better a good number of the same exact recipie, all with very controlled conditions, estimating your FG is probably best considered an educated guess.

Bottom line is if you want to do SNA's, you can probably pick any random point after the first initial burst of fermentation has completed to add the additional nutrients...

Ok, thanks for the information. I guess I'll take your advice and add it at a random point? Does anyone know about my second question, if it will affect the aging process?

Staggering won't change the aging process much from what I've been able to see, though making sure enough nutrients (in total) are there does make a difference. The faster ferment needing longer aging rule is often true, but the primary driver of that is fermentation temperature. Higher temp = faster ferment = longer aging. This not, however, an absolute rule as I have made delicious mead that only need to age for a year that was fermented at 84F, but few recipes will do that. Using nutrients may lead to faster ferments (taking weeks rather than months), but well-nourished yeast produce fewer off odors and flavors, and really long ferments may be prone to higher acetic acid levels. So proper nutrition = less-aging-required in many cases.

While there is no specific point at which you must add nutrients, you'll probably see better results if you get them added in during the first 1/3 of fermentation. Adding 1/2 of the nutrients after lag phase (when evidence of fermentation first becomes visible) and adding the the other half at the 1/3 fermentation point works pretty well. To determine the 1/3 fermentation point, assume your final gravity will be 1.000 (this works in most cases, except for very high gravity musts). So it you start with a gravity of 1.100, the 1/3 fermentation point is 1.067 (the half-way point would be 1.050).

It isn't crucial to hit these targets exactly, but being in the ballpark is good. If you wait too late, the yeast become unable to assimilate ammonium nitrogen and the nutrients won't be much help.

Thanks, that helps a lot.