ABV calculation? - Home Brew Forums

 Home Brew Forums > ABV calculation?

11-14-2011, 05:36 PM   #1
HopsyTurvy
Recipes

Sep 2011
Norman, OK
Posts: 10

Ok so... I know in order to calculate your ABV you need your OG and your final gravity and the temp at which you are taking the SG measurements.

I have some pear cider fermenting and the SG is down to 1.02, it's slowed , but im hoping it comes down just a lil more. However, I was unable to get any initial gravity reading due to a friend borrowing my hyrdometer and not returning it in a timely fashion. Is there anyway to find out the alcohol content of my cider??

11-14-2011, 05:42 PM   #2
Jacob_Marley
Recipes

Sep 2011
Detroit
Posts: 1,174
Liked 270 Times on 201 Posts

yes, though it's a bit of a pain in the butt.
Obtain another sample of your base pear juice. Check the SG on that. Then, figuring in any amount of additional sugars you've added and any total volume additions, you would be able to figure an approximate OG ... and then be able to figure ABV.

11-14-2011, 05:55 PM   #3
HopsyTurvy
Recipes

Sep 2011
Norman, OK
Posts: 10

Ya... I don't have the ability to obtain another sample of the base pear juice. It came from pears I juiced myself and the pears came from a couple pear trees in my back yard. I used all the pears on the trees the first time around... so obtaining another sample of base juice ins't really possible.... So, with that option off the table do i have any other options?

11-14-2011, 06:27 PM   #4
ajbram
Recipes

Oct 2011
Cornwall, Ontario
Posts: 371
Liked 22 Times on 16 Posts

I have a method that would provide a rough estimate, but would be a lot more fun than doing math.... Drink six ciders in an hour, rate your level of drunkenness. Then, the next day repeat with beverages of known ABV that's lower than your anticipated cider ABV. Keep repeating daily with beverages of known ABV until your drunkenness approaches your cider range.
__________________
Back off man! I'm a Scientist.

11-14-2011, 06:36 PM   #5
Jacob_Marley
Recipes

Sep 2011
Detroit
Posts: 1,174
Liked 270 Times on 201 Posts

There are other ways but none are very practical for your purposes. You can read an old blurb here on some other ways of determining ABV if you like ... it's pretty much sleep-time reading material tho.
http://www.homebrewtalk.com/f25/sg-q...5/#post3368467

Note my comments on using a vinometer there ... something that one otherwise might think to turn to ... but even the suspended colerant in red wine makes a vinometer inaccurate. I'd think peary is probably out.

Fresh pressed pear juice will run within a range of SG.
I did a quick google search and found one person stating that their fresh pressed pear juice had an SG of 1.065. This is a bit higher than most cider and apple juice I've seen which seems to run in the 1.040 to 1.050 range commonly ... though I'd expect that the juices would be somewhat similar. If pear juice's range is similar to apples, then the spread of 1.040 to 1.065 is useless in calculations as it is too broad a range.
You might specifically ask online to people who make Peary (hard pear cider) ... other than that ... guessing by taste is about the only other alternative.

11-14-2011, 06:39 PM   #6
HopsyTurvy
Recipes

Sep 2011
Norman, OK
Posts: 10

Quote:
 Originally Posted by ajbram Drink six ciders in an hour, rate your level of drunkenness.
Haha, while that would be quite an enjoyable method I was hoping for something slightly more accurate. Im worried im just outta luck.

11-14-2011, 06:45 PM   #7
HopsyTurvy
Recipes

Sep 2011
Norman, OK
Posts: 10

thanks, i'll look up on that old blurb. I wish i had been able to get an OG. There has to be some method out there for finding out how much alcohol is in a substance. I can't be the only person that has run into this dilemma... hopefully