question on abv

[robsan77]

For my first brew If i am brewing 20ltrs with a mash of
maris otter 3500g
caramalt 175g
tor wheat 50g

How do I get a desired abv? I want 4%

Sorry if this is a stupid question but I am a little unsure as to what I need to be aware of.

 

[Wez]

Hey :thumb:

Try the recipe calculator :thumb:

recipes.php

 

[rickthebrew]

click on the recipe calculator on the top of the page :thumb:

 

[Muddydisco]

Wez beat me to it! :evil: Or try some brewing software, Promash , beersmith etc theres loads out there!

 

[robsan77]

how do i use that? not sure what you mean. How will I know what the gravity reading will be after fermentation?

 

[Muddydisco]

Add in your grains, add in your hops and the calculator works out the Starting Gravity and an Estimated Final Gravity then if you need change your grains to raise or lower the Starting gravity :thumb:

 

[robsan77]

ohhhhhhhhhhhh I see. I was looking at the calculators page. doh

 

[robsan77]

the caramalt I have purchased is 20L but it isnt on the list! any help?

 

[robsan77]

sorry, just spotted they have a 30L will use that

 

[Muddydisco]

Post on here giving all the details that Bob Needs and He'll add it to the calculator
viewtopic.php?f=14&t=2203

 

[jamesb]

Could I point you towards the forumRecipe calculator?

I've put your recipe in there for you - here

The ABV will depend on a few factors. First off, your brewhouse efficiency will determine your original gravity. Assuming 75%, which is what the majority of us get, you'll get an OG of 1042.

The yeast used, and it's attenuation will determine the final gravity. Some yeasts won't ferment out as well as others. S0-4 is pretty good at getting a good attenuation. If you assume that it will finish at 1011, then the ABV will be (OG-FG)*k

k depends on the gravity drop, but for an ale in 4% range it's 0.129. You can find out more information from the HMRC site here.

So (1042-1011) * 0.129 = 4%

(Hmmm. Our calculator differs slightly but never mind)

You'll find that gravities always differ slightly between batches anyway, so you're better off thinking in terms of original gravity rather than ABV anyway.

EDIT: Beaten to it. BTW, Caramalt is pretty much the same as Carapils. If you really need to know how the contribution of each malt matters then you need to look into potential extraction. It's too late for my brain to work to explain it tonight ;-)

 

[evanvine]

RS
All of the above advice is excellent, but for your first brew I would concentrate more on the method than trying to hit a precalculated ABV.
Use a tried and tested recipe
Measure your starting gravity and final gravity, treat the figs after the decimal point as whole numbers and divide by 7.46.
EG OG 1.040 FG 1.010
40 - 10 = 30
30 Div 7.46 = 4.02
ABV = 4%
Just a thought!