Sugar breaks and SNA timing

This is mainly about calculating when to add nutrients during SNA (Staggered Nutrient Additions), not the benefits of specific dosages, or dosage regimes; that's for another post.

So what the hell is a sugar break? Think of it as a mile marker, that's all it really is, there's no physiochemical change in yeast performance (there are changes, but that just clouds the water of our clear atoll here), or important kinetic changes inherent at these events (though some appear as a byproduct of choices made regarding treatment at certain mile markers).
Let's talk wine for a minute to get a picture.The average grape wine (traditionally) starts around 23*Bx (SG ~1.097), and it will probably finish close to -1*Bx (SG 0.996). So a total consumption of about 24*Bx or 101 gravity points worth of sugar will have been consumed:
(this is the historical format for SG which is 1000 times our standard fractional SG form of 1.XXX)
So, when is fermentation half done? Half of 24 is 12, so when the yeast have eaten 12*Bx of sugar, they are half done (ie, 23 - 12 = 11; 11*Bx is the halfway mark). The same calculations work with gravity points (1,097.0 - 50.5 = 1,046.5).So, when you here wine people talk about the 1/3 sugar break, you can calculate it like this:
FG: -1*Bx                                                                 FG: 996.0
23 - (-1) = 24                                                           1097 - 996 = 101
24 * 1/3 = 8                                                              101 * 1/3 = 33
23 - 8 = 15                                                               1097 - 33.7 = 1063
1/3 sugar break = 15*Bx                                        1/3 sugar break = 1.063

That's all well in good for wine world where you know both your initial and terminal gravities, but we don't always know our FG in mead land. What if I have a mead with an OG of 1.130? It probably won't finish at 0.99X, it will probably be sweeter. That's where yeast tolerance comes into play. Let's take D47 as an example:
D47 tends to chew through about 100 +/-4 gravity points (~23.8*Bx)
That's all well in good for wine world where you know both your initial and terminal gravities, but we don't always know our FG in mead land. What if I have a mead with an OG of 1.130? It probably won't finish at 0.99X, it will probably be sweeter. That's where yeast tolerance comes into play. Let's take D47 as an example:
D47 tends to chew through about 100 +/-4 gravity points (~23.8*Bx)
D47: 23.8*Bx                                                           D47: 100 points
30.2 - 23.8 = 6.4                                                      1130.0 - 100 = 1030.0
FG ~ 6.4*Bx                                                              FG ~ 1.030
30.2 - 6.4 = 23.8                                                      1130.0 - 1030.0 = 100
23.8 * 1/3 = 7.9                                                        100 * 1/3 = 33
30.2 - 7.9 = 22.3                                                      1130.0 - 33 = 1097.0
1/3 sugar break = 22.3*Bx                                     1/3 sugar break = 1.097
When calculating the 1/3 sugar break for meads, it is necessary to estimate the FG based on the yeasts alcohol tolerance or average amount of sugar consumed (as gravity points or *Brix).

When to feed? That depends on your SNA schedule, but generally there will be at least 2 feedings (one at onset of fermentation, and 1/3 sugar depletion). Some may have many more, but the trick is to spread them out evenly (or close to even) over the first third of fermentation. Let's see some options for a must with an initial gravity of 26*Bx (SG 1.110), assuming a terminal gravity of -1*Bx (SG 0.996):

OG: 26*Bx                                                                    OG 1110.0
FG: -1*Bx                                                                      FG 996.0

26 - (-1) = 27                                                                 1110 - 996 = 114
27 * 1/3 = 9                                                                    114 * 1/3 = 38
26 - 9 = 17                                                                     1110 - 38 = 1072
1/3 break = 17*Bx                                                        1/3 break = 1.072
When calculating the 1/3 sugar break for meads, it is necessary to estimate the FG based on the yeasts alcohol tolerance or average amount of sugar consumed (as gravity points or *Brix).

Here are more possibilities:

Just follow the same color.
Red = 10 feedings (1/27^th breaks)
Blue = 7 feedings (1/18^th breaks)
Green = 5 feedings (1/12^th breaks)
Yellow = 4 feedings (1/9^th breaks)
White = 3 feedings (1/6^th breaks)