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 Duane 05-07-2012 03:11 PM

Finding ciders ABV

Is it possible to find the ABV of my cider? OG was 1.07. After that fermented out most of the way I transferred to a secondary, took another reading of 1.01, and THEN added two cans of apple concentrate to my 3 gallon batch. This has now fermented out all the way and I'm about ready to add priming sugar, test gravity again, and bottle.

Did adding all the extra fermentables halfway through make my OG irrelevant?

Thanks!

 kamkamdac 05-07-2012 06:27 PM

your OG can still be used to find a minimum ABV and then estimate final ABV by finding how much sugar was in the concentrate, i think its 1 lb of shugar is roughly = to 10 points, but if thats wrong im sure someone will correct me. its your FG which is now irrelevant, the only point of checking gravity at this point is to see when its done (around 0.995)

if you did ferment all the way out (lets say G=1.000 for estimate sake), then
.070x131.57=9.21 ABV, (9.87 ABV if fermented to 0.995)

assuming 5 gal batch and 12 oz cans of concentrate
(9.21x5)/5.188= min 8.876 ABV (min 9.5 ABV if fermented to 0.995)

starting with the min ABV just find how many grams of sugar were in the concentrate and from that find how many grams of sugar you added to the cider. convert grams to lbs, convert lbs to gravity points and there you go.

 kewlio250 05-07-2012 06:34 PM

Quote:
 Originally Posted by Duane (Post 4063982) Is it possible to find the ABV of my cider? OG was 1.07. After that fermented out most of the way I transferred to a secondary, took another reading of 1.01, and THEN added two cans of apple concentrate to my 3 gallon batch. This has now fermented out all the way and I'm about ready to add priming sugar, test gravity again, and bottle. Did adding all the extra fermentables halfway through make my OG irrelevant? Thanks!
no, nothing is possible, everyone just takes wild guesses as to the potency of theire drink, JK, kamkamdak nailed it

 GinKings 05-07-2012 08:00 PM

You need to take a final gravity to get an accurate answer.

You had 3 gallons with an OG of 1.070. Two cans of concentrate is roughly 0.2 gallons, so batch size is now 3.2 gallons. Ignoring the sugar in the concentrate for a second, the OG in the larger batch would be 1.066
1.070 * 3 / 3.2 = 1.066

One can of concentrate typically adds 17 points to a one gallon batch. Two cans would add 34 points in a gallon batch. In a 3.2 gallon batch two cans would add approx. 11 points.
34 / 3.2 = 11

1.066 (or 66) + 11 points = 1.077

Once you know your final gravity (FG), you can subtract it from your OG to calculate your ABV. If it ferments to 1.000, you'll have approx. 10% ABV. 0.993 would be about 11% and 1.008 would be around 9%

Quote:
 Originally Posted by kamkamdac (Post 4064629) i think its 1 lb of shugar is roughly = to 10 points, but if thats wrong im sure someone will correct me. its your FG which is now irrelevant, the only point of checking gravity at this point is to see when its done (around 0.995) starting with the min ABV just find how many grams of sugar were in the concentrate and from that find how many grams of sugar you added to the cider. convert grams to lbs, convert lbs to gravity points and there you go.
Your FG is relevant. You need to know how far it fermented. One lb of sugar adds 45 points (1.045) in a one gallon batch. In a 3 gallon batch it would add 15 points (45 / 3 = 15). Nutritional labels usually express sugars in grams. Converting to lbs isn't necessary. It's easier to do the math in grams. 10 grams of sugar will raise one gallon by 1 point. For example, if your two cans of apple juice concentrate contain 340 grams of sugar, you just divide by ten and get 34 points in one gallon. Simple. When doing calcs this way, always expess gravity to three decimal places to avoid confusion. 10 grams of sugar per gallon raises the gravity by 1.001, not 1.01.

This thread is kind of old but hopefully someone will see this and have the answer I need. All of the information is really helpful (thank you) and gets me almost everything I need. I have just one missing piece of the puzzle:

For the purposes of fermentation and effects on gravity and ABV, are all sugars created equally? In other words, does 10 grams of sugar from honey have the same effect as 10 grams of sugar from DME or 10 grams of sugar from raw peaches (and on and an and on ...). I know that I may need different volumes of a given substance to get the 10 grams of sugar (e.g. 1/8 pound of dextrose vs. 1 apple vs. 1 cup of LME), but once I get it translated down to grams of sugar, am I OK to use all of the equations above?

 Duane 12-06-2012 09:13 PM

So long as the sugar is fermentable, and not something like lactose, yes. A quick google search on any sugar should tell you whether or not it's fermentable. Cheers!

OK. And fermentable is a binary state, right? In other words, it's either fermentable or it's not, and not a situation of "more fermentable" or "less fermentable"?

 Duane 12-08-2012 05:15 PM

I'm no expert, but that is my understanding. Assuming, like you said, that you're not taking into account non-sugars that come along in various percentages with anything from fruit juice, to brown sugar, to malt, then my understanding is "fermentable" is a binary state. eg. the fermentable portions of apple juice are 100% fermentable, just as the fermentable portions of malt.

But again, I'm no expert.

That sounds right to me. So when people say X is more fermentable than Y, they mean X has a lower percentage of non-fermentable material in the total mass than Y does.