Posts Tagged With: ABV

My Rudimentary Alcohol Maths – working out the ABV

It’s been almost a week since I kegged my beer and I am finding that waiting is the hardest part. I am anxious to let the nectar flow and find out how it tastes… but patience is a virtue.

So in the mean time lunch breaks at work are spent reading brewing blogs, forums and books in an attempt to continue absorbing as much information as I can.

One point that I‘ve found comes up often is the question of working out the alcohol content of your home brew.

Alcohol Content

It is a valid question, but I’ve actually found it pretty hard to pin down a precise answer – as different brewers seem to favour different formulas.

However, one constant in the alcohol maths is the main tool you use when gathering the numbers – of course, I’m talking about the hydrometer.

As you’ll no doubt be aware the hydrometer is used before fermentation (to find the original gravity – OG) and after fermentation (to find the final gravity – FG).

It is the difference between these readings that form the building blocks you require when working out how much alcohol has been produced by the yeast – when they’ve been snacking on the sugars in your beer.

The formula I have settled on for predicting the ABV (alcohol by volume), and one that I am fairly confident works well, is as follows:

ABV% = ((OG-FG) x 105) x 1.25)

Full disclosure: I’ve yet to find information explaining why 105 and why 1.25, but there we are.

With my recent extract home brew, the OG was 1.043 and the FG settled out at 1.012. Using the above formula this means that I have a beer on my hands (ok, in my pressure keg… don’t worry I’ve not contaminated the beer by sticking my hands in there) of around 4.06%.

ABV Reference Table

The reason I am happy with this formula (aside it being fairly straight forward – I should have paid more attention in maths at school!) is that in John J Palmer’s book “How to brew” I found a reference table for working out alcohol content.

Now, although this table is a general overview and should be taken with a pinch of salt, it does give you a nice reference point for you to check whether your formula conforms – the formula I use does.

Based upon John J Palmer’s table, I have made my own (apologies, it is rather crude due to width issues):

Original Gravity
Final Gravity 1.030 1.035 1.040 1.045 1.050 1.055 1.060 1.065 1.070 1.075
0.998 4.20 4.86 5.51 6.17 6.82 7.48 8.14 8.79 9.45 10.11
1.000 3.94 4.59 5.25 5.91 6.56 7.22 7.87 8.53 9.19 9.84
1.002 3.68 4.33 4.99 5.64 6.30 6.96 7.61 8.27 8.92 9.58
1.004 3.41 4.07 4.72 5.38 6.04 6.69 7.35 8.01 8.66 9.32
1.006 3.15 3.81 4.46 5.12 5.77 6.43 7.09 7.74 8.40 9.06
1.008 2.89 3.54 4.20 4.86 5.51 6.17 6.82 7.48 8.14 8.79
1.010 2.63 3.28 3.94 4.59 5.25 5.91 6.56 7.22 7.87 8.53
1.012 2.36 3.02 3.67 4.33 4.99 5.64 6.30 6.96 7.61 8.27
1.014 2.10 2.76 3.41 4.07 4.72 5.38 6.04 6.69 7.35 8.01
1.016 1.84 2.49 3.15 3.81 4.46 5.12 5.77 6.43 7.09 7.74
1.018 1.58 2.23 2.89 3.54 4.20 4.86 5.51 6.17 6.82 7.48
1.020 1.31 1.97 2.62 3.28 3.94 4.59 5.25 5.91 6.56 7.22
1.022 1.05 1.71 2.36 3.02 3.67 4.33 4.99 5.64 6.30 6.96
1.024 0.79 1.44 2.10 2.76 3.41 4.07 4.72 5.38 6.04 6.69

This is based upon table 10 in How to Brew: Everything You Need to Know to Brew Beer Right for the First Time by John J Palmer – page 98.

This table uses the formula stated earlier in the post and is for reference only – don’t take it as gospel.

Categories: Brewing Information | Tags: , , | Leave a comment

Create a free website or blog at

Jan Harding

Artist in my Spare Time...


The proof is in the drinking

The Apartment Homebrewer

Brewing small batches of craft beer in a 650 sqft apartment

Bier Battered [.] com

Cheesey Movies & Craft Beer Pairings, brews from New Jersey and beyond

We make home brew

A blog about tasty home brew and beer.

It's that Craig Heap guy

A Welsh Beer Blogger celebrating the great ales of Wales

Blogging at World of Beer

the temporary home of Stephen Beaumont's World of Beer

Oh Good Ale

Phil's beer blog

Tim Hampson's Beer Blog

The quest for the perfect beer

The Great Canadian Beer Snob

Your guide to the wonderful world of beer!

The Mostly Harmless Brewing Co.

Homebrewing in The ATL


'Zee-tho-fyle', by Martyn Cornell, an award-winning blog about beer now and then, founded in 2007

sounds like beer

Beer & Music. Nothing Else Matters

I Think About Beer

& I Think About Cider - Belgian Beer & European Cider

The BeerCast

Scotland's beer website

The Good Stuff

Good Food. Good Beer. Good People.


Brewer with a Brewery Problem. Tui, Fyne Ales, Thornbridge, Epic, Good George, Brew Mountain and Fork & Brewer.

Jotham Brewing

the musings of an amateur home brewer

The Beer Nerd

A Diary Written With Beer

Alebagger's Beer Blog

Alebagger's exploration of the world of ale, pubs, brewing and all things beery.

Beers are a Changin

Exploring the best craft beers and brewers in Australia


Beersay - unverified, unofficial information gained or acquired from various sources or sauces about beer.....probably


Multi award-winning beer writer and author

Alcohol And Aphorisms

Whisky and Beer Discussion In A Relaxed, Yet Slightly Pretentious Fashion

Good Beer Better Hats

Our Hats are Off to You! ~Cheers~

Barley's Homebrewing Supplies

101-455 East Columbia St, New Westminster, B.C. 604.553.1941


A detailed blog following my homebrew and craft beer endeavors

Jay's Brewing Blog

Tips, tricks, hacks and more for everyting you need to make great beer, wine and mead.

Chris Hall | Beer

Craft. People. Places. Stories. Culture.

Craft Beer Reviews & Commentary by HomeBrewedHero

4 out of 5 dentists recommend this site


Beer brewing in Leeds

Apuhihi View

Thoughts from a previous coast (Mostly about my home-brew adventures)

Learning to Craft Beer

Making craft beer is one of the best hobbies ever. Let's talk about it. is the best place for your personal blog or business site.