Mosti Mondiale Does a raisin pack raise the SG

[Thig]

I started a MM La Bodega port kit Sat with a starting SG of 1.100, added the raisin pack Sunday as instructed. SG today is 1.085. Did the raisin pack add anything to the SG in between the starting and the current 1.085? Just trying to keep track of the abv being created.

 

[Rocky]

Any additional sugar would raise the SG. You have fermentation occurring at the same time so it will be difficult to estimate how much the SG was affected.

 

[Thig]

Any additional sugar would raise the SG. You have fermentation occurring at the same time so it will be difficult to estimate how much the SG was affected.

Yeah that's sort of what I thought, just wish I knew how much the raisin pack affected it. I plan to step feed some sugar into it and maybe even add some Brandy at the end, shooting for 20% abv.

 

[seth8530]

One thing you could do ( not too hard) is you could figure out how much sugar is on the grapes you added, make an assumption about how much sugar it will actually provide, and then add that to your total sugar inventory and come up with a calculated brix/SG.. BTW, if making a brandy be careful if you intend on step feeding and claiming you hit 20% abv, most people do not account for the dilution caused by adding SS during the step feeding process.

 

[Thig]

... make an assumption about how much sugar it will actually provide...

That is sort of where I got stumped, I think I will make the assumption that it added none and maybe that will offset the dilution caused by the added volume of the simple sugar. That way maybe I will get close to the 20%.

 

[seth8530]

I feel like it would safer to assume it adds closer to its full amount of sugar and then you could mathematically account for the dilution. If you are interested I have an equation that I made that accounts for dilution from step feeding.

 

[Thig]

I feel like it would safer to assume it adds closer to its full amount of sugar and then you could mathematically account for the dilution. If you are interested I have an equation that I made that accounts for dilution from step feeding.

I agree on the volume, just not sure we are on the same page with the SG. Let's assume no fermenting was taking place, how much would the bag of raisins raise the SG. You said to just approximate it but I have no idea.

 

[seth8530]

How comfortable are you with using math in an applied manner?

Let me run you through a hypothetical example.

First give this link a look, it list SG, BRIX, sugar in grams per liter and ABV potentials based on brix.
http://www.brsquared.org/wine/CalcInfo/HydSugAl.htm

Assume your current SG is 1.040, that means you have 110 grams per liter sugar in your wine. Multiply this by your wines volume in liters to find the total amount of sugar in your line.. Say 25 liters... 25*110= 2750 grams of sugar in your wine yet to be consumed.

Then take the sugar content ( from nutritional label) of the raisins you added, say 1kg of raisins has 100 grams of sugar in it. Lets say you add 5kg of raisins to your wine, this means you would add 500 grams of sugar to your wine.

Now with this 500 grams we can say all of it or say maybe 80 percent of it becomes fermentible.. In the case of 80% we would say that the wines total sugar content is now

(500*.8)+2750=3150 grams of sugar in your wine. Now to make this usefull once again for your standard run of the mill abv equations you need to divide 3150 grams of sugar by your current volume of liquid. In the case of raisins it is most likely still 25 liters.

3150/25 = 126 grams per liter of sugar. Now try and find that on the chart again. the closest that we find is 123 grams per liter which is rather close so no need to interpolate values. 123 grams per liter refers to a sg of 1.045. So you could infer that your adjusted SG accounting for the raisins being added is 1.045 instead of 1.040

These numbers were of course all off the top of my head since I do not have a pack of raisins with me, but you get the point..

Do you understand how I got the values that I got?

 

[Thig]

Then take the sugar content ( from nutritional label) of the raisins you added...

I am a CPA so I am rather good with numbers. Thanks for going through this and in the course of doing so you hit on what I was asking all along. I guess I was just asking the question the wrong way. I kept asking how much the raisins would raise the SG, but if I knew the sugar content I could make the calculation.

This pack of raisins came in a clear package as part of my MM La Bodega kit so I don't think there was any nutrional information on it. I will compare it to box of raisins in the grocery store and see what it says about the sugar content.

Thanks.

 

[seth8530]

Of course, NP. If you are interisted in step feeding calculations i would also be glad to help.

 

[Thig]

Just to follow up on this a little, after some digging, 1 pound of raisins has about 320 grams of sugar. That is equivalent to 1.28 cups of sugar. So 1.28 cups of sugar should raise the SG of 1 gallon by about .0225, this is equivalent to about 3% abv if it ferments dry. So the way I am looking at this, adding 1 pound of raisins to my 3 gallon batch La Bodega should have yielded about a 1% boost in abv.