How to Find Alcohol Content In Double Brewed Beer

boboboland

I NEED HELP!!!!

I have a Belgian Ale brewing at the moment. I took the S.G. reading at the start and it was 1.048. I have no problem figuring out the alcohol content if i just brewed it as normal but this one requires me to add spray malt when i transfer to the secondary along with some of the yeast down the bottom. So how can i figure out the final S.G. after altering the suger content during brewing. I can't find info on this anywhere.
Thanks in advance to anybody who helps me.

PabD

Is that the Muntons Belgian ale kit? Bought one recently but haven’t started it yet.

I was thinking of taking the SG at the start and then again before the addition of the spray malt to calculate the alcohol content up to that point. From there take the SG after the spray malt is added and again at the end before. If the two calculations are added together would it not give the total alcohol content? Not sure if it can be done, just thinking out loud

loyatemu

Use a brewing calculator - won't be 100% accurate but it'll be close enough.

BeerNut

Yep, add up the total weight of all the fermentables and punch it into some brewing software (like BeerTools, it's free) along with the volume of liquid. That'll give you a starting gravity. Then use your actual finishing gravity to calculate the ABV.

boboboland

PabD wrote: »

Is that the Muntons Belgian ale kit? Bought one recently but haven’t started it yet.

I was thinking of taking the SG at the start and then again before the addition of the spray malt to calculate the alcohol content up to that point. From there take the SG after the spray malt is added and again at the end before. If the two calculations are added together would it not give the total alcohol content? Not sure if it can be done, just thinking out loud

Yea that's the one. I was thinking about doing what you were saying like take both the primary and secondary fermentation both as separate and then just add both results but i'm not sure if that'll work. They reckon 7.5% so i'll just try it and see what result i get from adding them together.
Either way regardless of the result i get i still think i'll have the same effect on me when i drink it whether i know the % or not.

boboboland

BeerNut wrote: »

Yep, add up the total weight of all the fermentables and punch it into some brewing software (like BeerTools[/URL], it's free) along with the volume of liquid. That'll give you a starting gravity. Then use your actual finishing gravity to calculate the ABV.

Was looking at that but it's a kit so i dunno what type of extract to select i tried it and it gave me like 12.5% doubt that's right anyway.

keppler

So you already have a reasonably accurate abv for what you've fermented to date (assuming that the process is definitely complete). There are algorithms available allowing you to calculate approximate abv from the fermentables added. One site I just looked at states that fermentables in grams/litres/16.83 = abv.
So 1 Kg of fermentables in 23litres = 2.58%

macnug

keppler wrote: »

So you already have a reasonably accurate abv for what you've fermented to date (assuming that the process is definitely complete). There are algorithms available allowing you to calculate approximate abv from the fermentables added. One site I just looked at states that fermentables in grams/litres/16.83 = abv.
So 1 Kg of fermentables in 23litres = 2.58%

I use a similar approximation, weight of fermentables x fermentablity / 20 / litres. So for dme 3000g x 0.8 / 20 / 23 is 5.2, of course that depends of the attenuation of the yeast but is a good way of guessing.

boboboland

keppler wrote: »

So you already have a reasonably accurate abv for what you've fermented to date (assuming that the process is definitely complete). There are algorithms available allowing you to calculate approximate abv from the fermentables added. One site I just looked at states that fermentables in grams/litres/16.83 = abv.
So 1 Kg of fermentables in 23litres = 2.58%

So what your saying is I Have a 3.5 Kilo Kit so according to the formula u provided is
3500/20.5/16.83=10.15%
Is that correct? Are all the extracts and spray malts completely fermentable? Is there a way of figuring out how much of it is fermentable?

macnug wrote: »

I use a similar approximation, weight of fermentables x fermentablity / 20 / litres. So for dme 3000g x 0.8 / 20 / 23 is 5.2, of course that depends of the attenuation of the yeast but is a good way of guessing.

I see you have 0.8 in your formula to lower the final answer to compensate for non fermentables in the wort but how did you come up with the 0.8 or is this just a ball park figure?

keppler

boboboland wrote: »

So what your saying is I Have a 3.5 Kilo Kit so according to the formula u provided is
3500/20.5/16.83=10.15%
Is that correct? Are all the extracts and spray malts completely fermentable? Is there a way of figuring out how much of it is fermentable?



I see you have 0.8 in your formula to lower the final answer to compensate for non fermentables in the wort but how did you come up with the 0.8 or is this just a ball park figure?

Nope,
what I am saying is that you should use the before and after sg readings to calculate the abv of your first fermentation and then use the formula for calculating the approx extra alcohol produced by the second fermentation with the new added fermentables. Then add the two abv's together for approx total abv. Yes you are correct about spray malts not being fully fermentable. What I am consistently reading on homebrew forums is that only about 80% of the mass added will be fermentable and this figure will vary whether you are using light, medium or dark malt. Others on here may be able to confirm this figure?
I've been reading up on how the alcohol is actually calculated using the hydrometer readings and its perfectly fine for you to take another sg reading when you add the spray malt to your secondary fermentation and then take another final sg reading when its done fermenting. treat them as two separate brews and add the two abv's for a total.

macnug

boboboland wrote: »

I see you have 0.8 in your formula to lower the final answer to compensate for non fermentables in the wort but how did you come up with the 0.8 or is this just a ball park figure?

Cant remember where I got it from tbh it was a few years ago, I just committed some of the figure's to memory, might have been john palmers book, I know the lighter dme is more fermentable than the dark but i use 80% as an average. Lme is about 70% and simple sugars like dextrose, honey etc is 99% ill try and find the source for you and post it, I'm just on the phone atm.

boboboland

macnug wrote: »

Cant remember where I got it from tbh it was a few years ago, I just committed some of the figure's to memory, might have been john palmers book, I know the lighter dme is more fermentable than the dark but i use 80% as an average. Lme is about 70% and simple sugars like dextrose, honey etc is 99% ill try and find the source for you and post it, I'm just on the phone atm.

Excellent. Thanks For Your Help

n97 mini

Take the gravity just before and just after you add the spraymalt. Then add the difference to the original gravity.