All this duscussion of PA has inspired me to ask, what calculation do you all use for sugar additions, esp. to large volumes? That is, if you know your initial volume of must, you know what what Brix you want to be at, and you know your starting Brix, how do you calculate how much sugar to add?
I know that 10g/L will raise the sugar by 1%, but that doesn't take into account volume changes caused by the addition itself.
Thanks for any help.
Dave
**************************************************************************** Dave Breeden snipped-for-privacy@lightlink.com
Here's the procedure (an example you can follow) that I posted and submitted to the original FAQ a few years back...
YOU HAVE: 18.93 L (5 US gal) @ SG 1.057 (say 146 g/L) = 2,764 g sugar YOU WANT: 19.93 L @ SG 1.095 (say 250 g/L) = 4,733 g sugar --------- difference 1,969 g
1lb sugar (454 g) takes up 0.29 L of volume, therefore
1,969 g x 0.29 L = 1.26 L volume. Good luck - Giovanni
OG 15 _TG 21_ 06 raise brix by 6 points....1.34 X 06 X volume of must=how much sugar to add in ounces..Divide the answer by 16 to get pounds..divide by 8 to get cups.
Is the equation 454 g of sugar = 0.29 L true after the sugar is dissolved? That is, does 1 l of water + 1 pound of sugar = 1.29 l of dissolved sugar and water together?
Thanks again!!
Dave
**************************************************************************** Dave Breeden snipped-for-privacy@lightlink.com
That looks right. I've just finished a batch of sugar syrup - 6L water and 8kg regular sugar, which came to about 11L of syrup. You can get the ratio from that, but it looks like what Giovanni said, more or less.
snipped-for-privacy@knology.net There is a really nice program for several wine making calculations at
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It is called WinCalc and allows you to punch either gallons or liters and will give you all kinds of goodies. I have had very good luck adding sugar to country wines and it works for me. Aubrey
I pretty much don't want a "balck box," though. I need to see a formula, and how the formula was derived.
My interest is in making additions to large volumes (1000 gals, whatever) in which the volume created by the sugar itself makes a differnce in the final calculation (i.e., if you calculate how much sugar you need to add to reach a certain Brix based on your original volume, that won't be enough to reach that Brix for the volume you actually create when you add sugar to your must).
Dave
**************************************************************************** Dave Breeden snipped-for-privacy@lightlink.com
That doesn't look right - plugging in some numbers: case 1: A , B@, Wkg gives 10*20/60 = 3.3kg case 2: A , B`, Wkg gives 10*40/40 = 10kg
So you'd need twice as much sugar for the same starting volume to go from 40B to 60B than from 20 to 40, which is the same delta. Even given the volume will jump up a bit after the 3.3kg, this can't account for the difference of that magnitude.
Actually, even simpler test - same starting weight, same desired Brix difference, but in one case you start at A of 20 and in another at A of 40. Your W(B-A) is the same in both cases, but your 100-B is different, so you're getting quite different S in each case although with the starting conditions they should be the same, no?
A follow up on my previous post, trying to get to the bottom of this: We have: Vs - starting volume of must Bs - starting Brix (not BS :) and sugar by weight in a given volume is V*B/100 (V in litres, weight in kg)
Then the basic formula is: starting sugar + sugar addition = resulting sugar: Vs*Bs/100 + dW = Ve*Be/100 (dW is added sugar by weight, e means "ending") This gives: Vs*Bs + 100*dW = (Vs+dV)*Be (dV is volume increase, so Ve Vs+dV) 100*dW = Vs*Be - Vs*Bs + Be*dV = Vs*dB + Be*dV
Here is the funny part - the dV is affected by Be, and therefore by Bs. If we assume that a given weight of sugar increases volume by a fixed amount, which seems to make sense and is a pretty standard assumption, then the formula says that you'd need more sugar the higher your Bs is to get the same dB. If this is the case, you can figure out how much volume increase you get from 1kg sugar and you'll have the final formula. But the result seems counterintuitive to me, I still can't figure out why the starting Brix would matter?
The other possibility is that the Bs doesn't matter. For this to work, dV would have to proportionally decrease with the rising B, i.e., the Be*dV should be constant for given dW, Vs, and dB. If this is the case, you'd have to figure out the formula between dW, Be and dV, which should be posible by doing some experiments. Again, I can't really explain why this would be the case, but it makes intuitively more sense to me. However, it goes against the assumption that volume increase depends directly on weight, which seems pretty much universal, so I don't know...
One way or another, some experimentation should tell you which is correct - hopefully one of them is!
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