Got some math questions, any help please?

[CaptainCookie]

So, I was brewing a 19L (5gal) batch with a couple of friend of our favourite Red Ale, for the pre-boil we hit a gravity of 1050 and we were presented with a question: how many grains (ounces) of table sugar we'll need to add to raise the pre-boil gravity by one?

this is a pure curious question, I know if we have problems adjusting the gravity we can just fix it by boiling, or that adding sugar to our beer can be a bad idea, we just got this hypothetical question, also

let's just say that adding 10 grams (0.352 Onz) of table sugar we raise our gravity by one, this result is just valid in our 19L (5gal) batch, right? or it'll the same value for a 5L (1.32gal) batch?

We choose the pre-boil for cuz is easy to handle, and we can know the exact volume, after the boil we can only assume the volume as we don't have any fancy equipment for measurements

By definition, one pound of table sugar, dissolved in a galon of water, we should hit 1046, in our 5 gal batch, we got 5x50 = 250 gravity points, if we add this disolution of sugar we are adding 46 gravity points, but at the same time we're messing around with the volume, so at the end I got three questions:

1. How many grams(ounces) of sugar is needed for raised my preboil gravity by one
2. this measurement it's volumen depent?
3. If I add the sugar dissolved in water, what it will be the gravity and the volume after?, how much sugar dissolved in how much water could raise my preboil gravity by one?

Thanks for the help guys, I would love to see the math behind so I can applied it for any other similar case, please take your time to explain your math, I'm kind new into all this, but I really want to learn

 

[PADave]

This should answer your questions.

http://winemaking.jackkeller.net/hydrom.asp

 

[CaptainCookie]

just about definitions, can somebody be more specific to this topic?

 

[Yooper]

just about definitions, can somebody be more specific to this topic?

It's volume dependent. Since table sugar has roughly 46 "points" in a pound per gallon, adding one pound in 5 gallons would give you an additional 9 points. Raising the OG from 1.050 to 1.059 in a 5 gallon batch for example.

 

[JR_Brewer]

1. How many grams(ounces) of sugar is needed for raised my preboil gravity by one
2. this measurement it's volumen depent?
3. If I add the sugar dissolved in water, what it will be the gravity and the volume after?, how much sugar dissolved in how much water could raise my preboil gravity by one?

First, let's get some terminology down. When you say raise gravity "by one," a lot of us would ask "one what?" While specific gravity (the ratio of the density (i.e., mass divided by volume) between your liquid to pure water) is a unit-less scale, we refer to 0.001 on the specific gravity scale as a "point." Now, on to the questions.

1. I'll assume you mean 1 point, and I'll further assume we're talking a 5 gallon batch. As Yooper so rightly pointed out, 1 pound of sugar dissolved in 1 gallon of water yields a SG of 1.046, but only 1.009 in a 5 gallon batch. Divide this by 9, and you'll see that 1/9 pound of sugar increases the gravity of a 5 gallon batch by 1.001, or "1 point."

2. Absolutely yes.

3. For this one, let's work through a few examples. Let's say you have a 5 gallon batch with a SG (temperature corrected of course) of 1.050. Let's say you want the batch to have a final gravity of 1.065 and you plan to make up the difference with sugar. Currently, you have 250 gravity points (50 x 5 gal) and you need 325 (65 x 5 gal), a difference of 75 points. Sugar has 46 points per pound per gallon, so we need to stir in 1.67 pounds (75 / 46) of sugar to make up the difference.

Example 2 - You only boiled 4 gallons and measured a SG of 1.050. Now you only have 200 gravity points. You plan to dissolve your sugar in a gallon of water and then add the solution to the wort. You still plan on a 5 gallons of 1.065 wort. You still want 325 points, so you'll need to make up 125 points with sugar. This time you'll need 2.78 pounds dissolved in your 1 gallon (FYI, that 1 gallon will have an SG of 1.125), and add that to your wort.

I recommend reading John Palmer's book, which is available on his site: http://www.howtobrew.com/

Hope this helps, and happy brewing.

 

[CaptainCookie]

Sweet, thanks, this is just what I was looking for, thanks a lot, sorry for the confusion about the definition, yes I mean increase a point

Example 2 - You only boiled 4 gallons and measured a SG of 1.050. Now you only have 200 gravity points. You plan to dissolve your sugar in a gallon of water and then add the solution to the wort. You still plan on a 5 gallons of 1.065 wort.

what if after the boil I ended with 4.4 gallons with SG of 1050, still with a final volume of 5 gallons of SG 1065, How would the calculation be?, sorry for the dumb question, I still getting used to it

 

[balrog]

I think you still want to use the points method.
4.4 gallons of 1.050 is 4.4 * 50 = 220 points
You want 5 gallons at 1.065 which is 5.0 * 65 = 325 points
So you want to add 105 points of sugar at 46 points per pound or 2.28 pounds but it gets tricky because you want to increase volume from 4.4 to 5 but that sugar will add volume also. You want to add 2.28 pounds then enough water to make 5 gallons.

And I think adding that much table sugar might alter the taste. Cidery I've heard.