### Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

#### TheBearMoon

##### New Member
So originally I totally forgot to do an OG read and knew better than to try it when I forgot, its been going 4 weeks now and I grabbed a reading (even tho I don't know which reading is the one to read HAH) but I know where the level has ended up. is there any online calculator or something I can put in my original recipe (i wrote it down thankfully) and I'm wondering if I can plug in somewhere to figure it out.

#### THESULLI

##### Well-Known Member
What was your recipe/process and your final gravity reading? Someone a bit more well versed than myself in Beersmith or other similar programs might be able to give you a basic idea of what your original gravity would have looked like.

##### Well-Known Member
You can definitely figure it out pretty close if you know how many lbs of honey and how many gallons of water you used. I’ve done the same thing because I mix up my mead each year at my Homebrew club’s annual Mead Day, which involves drinking past years’ meads and leads to forgetting things.

Post your recipe and we’ll figure it out with this formula:

(((#lbs/gals) X (7*#gals))/1000) + 1 = SG

example: 13.5lb honey and 5 gal water

(((13.5/5) X (7*5)) / 1000) + 1 = 1.0945

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#### RPh_Guy

##### Bringing Sour Back
You can definitely figure it out pretty close if you know how many lbs of honey and how many gallons of water you used. I’ve done the same thing because I mix up my mead each year at my Homebrew club’s annual Mead Day, which involves drinking past years’ meads and leads to forgetting things.

Post your recipe and we’ll figure it out with this formula:

(((#lbs/gals) X (7*#gals))/1000) + 1 = SG

example: 13.5lb honey and 5 gal water

(((13.5/5) X (7*5)) / 1000) + 1 = 1.0945
That equation definitely isn't right. It doesn't take into account the volume.

Here you go, this assumes 36ppg, which is probably correct to within about 10%:
0.036 * [pounds of honey] ÷ [total volume gal] + 1 = s.g.

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##### Well-Known Member
Been a while, but it worked for me when I tested it with a future batch after the forgotten one. Perhaps the problem is that one of the numbers for #gals in my equation is total must volume. Or maybe both? I forget - sorry!

#### Rackrunner

##### Well-Known Member
Was it an all grain batch or extract? The formula RPh_Guy posted is correct for extract, honey, etc if you are just adding sugars into the boil, where the assumption is 100% 'mash' efficiency. For an all grain batch, you need to figure in your typical efficiency to get closer to the real numbers, even if it's just a guess to account for absorption, losses etc.

It can vary a little bit with your grains, but 36 ppg (points per pound per gallon) is a good starting point.

((0.036 * [pounds of grain]) * [your efficiency, like 80%]) / [total post-boil volume] +1 = SG.

#### RPh_Guy

##### Bringing Sour Back
Been a while, but it worked for me when I tested it with a future batch after the forgotten one. Perhaps the problem is that one of the numbers for #gals in my equation is total must volume. Or maybe both? I forget - sorry!
In your equation you divide by the gallons and then multiply by the gallons, so they cancel out. You can literally put any number and it won't change the result. It's only approximately correct for 5 gallon batches. The 7 came from dividing 35ppg by 5gal.

#### Bandua94

##### New Member
You can definitely figure it out pretty close if you know how many lbs of honey and how many gallons of water you used. I’ve done the same thing because I mix up my mead each year at my Homebrew club’s annual Mead Day, which involves drinking past years’ meads and leads to forgetting things.

Post your recipe and we’ll figure it out with this formula:

(((#lbs/gals) X (7*#gals))/1000) + 1 = SG

example: 13.5lb honey and 5 gal water

(((13.5/5) X (7*5)) / 1000) + 1 = 1.0945
Now what if you added fruit beforehand?

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