Alcohol Increase Whilst in Bottle ?

[Slate Miner]

Last weekend I bottled up my first brew (Woodforde's Wherry), the general opinion is to leave in the bottles for several weeks as the ale improves with age. My question is, does the strength of the beer increase whilst in the bottles, and if so by how much? :

 

[Baz Chaz]

I would think it might increase microscopically as you've introduced a small amount of sugar to prime it

..... but realistically, if there is an increase, you are talking about a very small difference

 

[pittsy]

, as long as it finished fermenting fully the sugar used for priming will be converted to gas by the yeast . Then while cool storage the yeast finds it too cold and drops away to the bottom of the bottles/keg doing nothing more .

 

[Slate Miner]

Thanks for the replies. :

 

[Moley]

The alcohol increase due to the priming sugars is only in the order of 0.1 to 0.2% abv.

Likewise, we often hear people say that they found a bottle of home made wine which had been stashed away and forgotten about for years and “it was like whisky”. Well the taste may have changed considerably over its extended maturation period and it should certainly be much smoother, but it won't be any stronger than the day it was bottled.

 

[klaus]

In the Coopers kit instruction leaftlet they show the formula for working out the ABV which includes an addition of 0.5 for the priming sugar, i.e ((SG - FG)/7.46) + 0.5.

Example, a brew I have just bottled (not Coopers) ((1060 - 1016)/7.46) + 0.5 = 6.4%
Of course this is approximate, I tend to assume it's a bit lower, allowing for inaccuracies.

 

[Moley]

Of course this is approximate, I tend to assume it's a bit lower

It's not approximate, it's just plain wrong.

To get an extra 0.5% abv you would have to prime at 10g sugar to the litre. In plastic this would give you gushers, in glass you'd have bottle bombs.

 

[klaus]

Of course this is approximate, I tend to assume it's a bit lower

It's not approximate, it's just plain wrong.

To get an extra 0.5% abv you would have to prime at 10g sugar to the litre. In plastic this would give you gushers, in glass you'd have bottle bombs.

OK - so the formula is overstated to give the impression of a higher ABV than you can normally achieve?

 

[daveozzz]

To get an extra 0.5% abv you would have to prime at 10g sugar to the litre. In plastic this would give you gushers, in glass you'd have bottle bombs.

The kits say to prime at the rate of 8g or 9g per litre which isn't so far off 10g..
eg. http://www.coopers.com.au/the-brewers-g ... hefeweizen

 

[shearclass]

Of course this is approximate, I tend to assume it's a bit lower

It's not approximate, it's just plain wrong.

To get an extra 0.5% abv you would have to prime at 10g sugar to the litre. In plastic this would give you gushers, in glass you'd have bottle bombs.

Coopers instructions advise 8g per litre, so not far off

 

[Dunfie]

Arithmetic time.

Sugar has a ldk (litre degree per kilo) value of 360. So if you dissolve a kilo of white sugar in a litre of water you would have a gravity of 1360.

If you dissolve a kilo in 23l you raise the gravity by 15.65 points (360/23).

I batch prime and normally use 80g per 23l. The raises the gravity by 1.25 points ((360/23)*0.08). I then multiply by 0.129 to work out the extra alcohol. It works out as an extra 0.16%abv.

Sent from my GT-I9100 using Tapatalk

 

[Darcey]

I have wondered. I allways cornie keg, however using a bottler I bottle the rest. ales about a flat tea spoon of sugar per 1pt and anything else a heaped one. I am going in to casking so I assume on a bigger scale it would be calculable?
D

 

[Moley]

Sugar has a ldk (litre degree per kilo) value of 360. So if you dissolve a kilo of white sugar in a litre of water you would have a gravity of 1360.

Well actually, if you dissolve 1kg of sugar in 1 litre of water you'd only have a gravity of about 1225, because you would end up with around 1.6 litres of syrup due to ‘sugar bulking’ (360 ÷ 1.6)

If you could boil 1kg of sugar to a syrup in 400ml of water (and allow to cool), then you would have 1 litre @ 1.360

Likewise, if you dissolve 1kg in 23 litres you raise the gravity by 15.25 points (360 ÷ 23.6)


However, I bottle prime at a level half tsp per pint, which is about the same as your 80g per 23l, giving less than 0.2% abv like I said in the first place, so we agree on that.

 

[Dunfie]

Well actually, if you dissolve 1kg of sugar in 1 litre of water you'd only have a gravity of about 1225, because you would end up with around 1.6 litres of syrup due to ‘sugar bulking’ (360 ÷ 1.6)

I think I am going to have to make a calculation change in my brew spreadsheet as I had overlooked that. :

 

[pjbiker]

Well actually, if you dissolve 1kg of sugar in 1 litre of water you'd only have a gravity of about 1225, because you would end up with around 1.6 litres of syrup due to ‘sugar bulking’ (360 ÷ 1.6)

I think I am going to have to make a calculation change in my brew spreadsheet as I had overlooked that. :

Easiest way is to batch prime. Measure your sugar and dissolve up in your boiled beer/water and the calculation is based on the mass of sugar added over the final volume in the vessel ie. whats in it plus the volume of what you add. I usually add about a pint of priming along with gelatin for fining to each keg, (23-26L). I go for 3.5g/L priming sugar for ales. The overall %ABV increase due to priming works out as about 0.15%. The official formulas can be found on HMRC website, here, number 32.
http://customs.hmrc.gov.uk/channelsPort ... e=document