specific gravity adjustment calculations....

[Rhu]

Hi all..

does anyone know of an online/downloadable calculator to work out how much sugar to add to a starting gravity to get the aimed-for gravity?

Does that make sense?

So if I start with 1 gallon of juice at 1.050 and want a gravity of 1.064 is there a little widget out there that will tell me, for different types of sugar how much to add..

Now I've found beersmith, but as far as I can make out it will only calculate gravity adjustments through DME or LME additions...

I have also found a thread on here that discusses this:

(https://www.homebrewtalk.com/f14/how-do-i-calculate-g-effect-sugar-additions-249672/)

....and I think I can work it through, with a pencil and paper....

so if 1lb of cane sugar equates to 46 gravity points in 1 gallon of water...I'm English so bear with me here, I need to translate it to metric..

453g of cane sugar (sucrose) equates to 46 gravity points in 3.68 litres of water..

so, if one has a gallon (3.68ltrs) of juice at 1.050 and wants an sg 1.064, then one needs to add 14 gravity points which will be 138g of sugar.....(assuming that you dissolve it directly into some of the juice that goes to make up your gallon)

Does this sound/look right?

anyway, original question stands, is there an online calc for this? Or do I have to get a spreadsheet out?


cheers

 

[oljimmy]

Rhu, that's exactly right, as far as I can tell. I made up a little spreadsheet for myself with the formula, but it takes no time at all, I highly reccomend having one around.

One thing, though: there are a variety of different reports on how many gravity points are added by various sugars. IMHO someone should do a comprehensive test: 1 gal of 1.000 water, add 1 lb of sugar, and measure the gravity point increase. I should really do this but I haven't yet. You could do it cheaply by scaling down... dissolving .1lb of your kind of sugar in 368ml water.

 

[Rhu]

ok, testers coming up for the sugars I have available...not sure exactly when...

Would it be worth starting a new thread with an easily searchable title with the results?

cheers

 

[oljimmy]

Absolutely!

Also, It would be really nice to know how many gravity points are added by apple juice concentrate. However, the math for this is much more complicated, because when you add a can of AJC, not only are you adding 160-ish grams of fructose, you're adding more liquid. So while the cane sugar, being soluble, won't increase the volume of your test liquid, AJC will. Thoughts on how to test that?

 

[Rhu]

very much more complicated, but not actually that complicated...took me back to Chemistry/algebra classes that I've not thought of in over 10 years.

you will definitely need a spreadsheet for this one, or a large sheet of paper.

I figured it out last night, I think.

If you don't care about the final volume you end up with then it's a bit easier, but if you want to fill (for example) a gallon jug and have a specific sg then it's more fun.

Basically you need to work out the Molar conc. of AJC and of your starting juice then you can calculate how much of each you need to mix together to end up with a juice with the required sg for a given final volume. Basically boils down to:

final conc. = total no. of Moles/total volume

(and here's me thinking it was rats that you put in cider!!)

I think you can assume that both AJC and starting juice are both dilute solutions of Fructose and starting from there work it out.

I've not seen AJC anywhere here so I can't work it out. Assuming that 1 packet/can of AJC will tell you how many grams of Fructose it contains, if you then add it to enough water to make 1ltr of solution (eg. if you have 500ml of AJC, add it to 500ml of water) you will then have a standard solution of AJC. Take the specific gravity and I can then fit it into the equation and write it out. It's a bit long winded though.

It won't be 100% precise but it should be close enough for government work.

Maybe a PM would be the way to go.

 

[ACbrewer]

One thing, though: there are a variety of different reports on how many gravity points are added by various sugars. IMHO someone should do a comprehensive test: 1 gal of 1.000 water, add 1 lb of sugar, and measure the gravity point increase. I should really do this but I haven't yet. You could do it cheaply by scaling down... dissolving .1lb of your kind of sugar in 368ml water.

I've seen what you are after here. and some of your chemistry isn't right

if you have 1 lb of sugar and add enough water to have 1 gallon, you will have 1.046 gravity. If you add 1lb of sugar to 1 gallon of water you will have slightly more than 1 gallon and slightly less the 1.046 (I think the number is like 1.043) There was I link I had - and of course can't find now - of a wine maker who had made all sorts of wines. And instructions on them, and most important to this discussion, a table with a breakdown of
amount of sugar added to 1 gallon and + 1 gallon. This would then tell the difference of adding the water to the sugar or the sugar to the water.

 

[Rhu]

Don't worry,

got it covered, I think, having gone back to chemistry 101 and reminded myself about Molar solutions volume=mass/density and all that jazz.

To make up the gallon you have to dissolve your sugar in some of the juice and then add more juice to fill the gallon.....'course, this does mean that you will be leaving some of your gallon of original juice to one side to drink 'virgin' but it should be a negligible amount and you will more than likely have to warm some of your juice, which would have the cider purists on here up in arms...but then they are unlikely to be adulterating their cider with sugar/AJC anyway so for the rest of us that are making Tree Top hooch it shouldn't be a problem!!

Really, I think it's more of an academic project- attempting to hit a specific sg in order to get a specific final gravity/ABV depends on yeast attenuation/fermentation temp all sorts of other things..fun though.

All of the winemaking charts I've found talk about sugar additions to achieve a specific sg, but none compare different types of sugar or in fact mention which type of sugar they are using.....I've just found this though

http://winecalc.software.informer.com/2.3/

but I'm on Mac, so it won't work for me. Therefore as a disclaimer: I have no idea if it is useful, works at all, causes your computer to catch fire or makes magic hats.

 

[oljimmy]

Ah, I see, good to know. Thanks! definitely not a chemist. I'd love to see a table like that.

 

[oljimmy]

Interesting, ha ha, let me know if you work that all out. That's exactly my complaint about online guides: so many just talk about "sugar" additions.

Now, that said, I've mainly stopped caring about where my SG is. I figure, it is what it is. If I can ballpark it I'll know basically what kind of cider I've got, and for homebrewers I don't know that it matters too much whether you start at 1.062 or 1.067. FINAL gravity tho, that's a different thing. of course, and for backsweeteners this sugar info is a big deal.

 

[Rhu]

If you can take an sg. for 1 can of AJC made up to 1 ltr. and let me know how many grams of carbohydrate in the can of AJC then I can send you an excel formula formula I think.

R