andyakameatloaf
Regular.
scheelings said:For those that don't:
Until this point, everything you said may as well have been written in Elvish to me.
And that's why I use a hydrometer.
scheelings said:For those that don't:
rpt said:Don't hold back. Tell him what you really think.anthonyUK said:For someone with an ounce of science knowledge that is a very stupid question with relation to brewing.
Those are the calculations that I use to work out my recipes and they all come in VERY accurately.
morethanworts said:Slightly OT, but ScottM - just interested...
Those are the calculations that I use to work out my recipes and they all come in VERY accurately.
...Have you tested any of your beer (or had it tested in a lab) to validate the calculations of alcohol content? I have no reason to doubt them - you've clearly looked much further into it than me, but it would be really interesting to know a calculation that has been tested on the resulting beer from someone who's done primary research.
I'm only a hearsay bio-chemist, when it comes to the science, I'm afraid!
The calculation for ABV is the one that HMRC stand by (IIRC).
alanywiseman said:I you really care to Scott I am sure someone at Herriot Watt in Edinburgh would be able to. They run a brewing and distilling degree. All it would take is to run it through a gas chromatography system to get the results.
morethanworts said:The calculation for ABV is the one that HMRC stand by (IIRC).
Likely to work out on the high side, then :lol:
WoW, do you know all this or is it a cheeky Copy & Paste?? :whistle: :whistle:scheelings said:When the chemistry is more accurate? (assuming all sugar is fermented)
For those that like Chemistry:
C12H22O11 + H2O + invertase => 2 C6H12O6
C6H12O6 + Zymase => 2 C2H5OH + 2 CO2
So 1 mol of sucrose yields 4 mols of ethanol.
Molar mass of sucrose = 342.30 g/mol (based on molecular weight)
Molar mass of ethanol = 46.06844 g/mol
Therefore 342.3g of sucrose, yields 184.273 g of ethanol
Or more conveniently, every 100g of sugar, yields 53.8g of ethanol
The density of ethanol is 0.789 g/cm³
1L ethanol = 0.789*1 => 0.789KG
Therefore 53.8g of ethanol = 68.23 millilitres of ethanol
This volume can be assumed to be produced for every 100g of sugar added as long as the alcohol threshold remains below the theoretical upper limit of the yeast.
For those that don't:
So every 1kg of sugar added to a 30 litre brew, increase the alcoholic content by 2.22%.
anthonyUK said:scheelings said:Can you tell the alcohol content from the final reading only?
For someone with an ounce of science knowledge that is a very stupid question with relation to brewing.
ScottM said:Not quite on the same level but I use a fairly complex FG calculation for when the sugar's are known. Obivously with grain brewing this is never going to be the case so it's fairly useless there, but when you know what you are putting into the brew... you can be fairly accurate with what will come out.
...
The assumptions of my calculation are:
You know (or can work out) exactly how much fermentables are being added to your brew.
You know (or can work out) the exact yield of what you are adding.
You know the attenuation of the yeast (Higher attenuation effectively means the yeast is less fussy with it's sugar varieties).
...
FG = OG + 0.624 - sqrt((((100/(1000*volume)*(total fermentability*0.645))*0.789*(yeast attenuation/100*1.33))/100.3)-(OG-(125.65/200.6))^2+0.7817+OG^2-(OG*125.65/100.3));
Russ146 said:For what its worth i never use one
To me its an unnecessary risk of contamination. I leave to ferment for 14 days at a constant temperature and transfer to a barrel. I'm now on my 20th kit with 100% success.
I then leave for at least 4 weeks and i make premium pub quality beer again and again.
As somebody said K.I.S.S it, you know it makes sense
scheelings said:+
Yes, I recognize the arrogance of my original post.
I think I could spend months just reading everything already posted here and just try to learn.
I'm overwhelmed with the number of responses I'm getting, the sheer amount of knowledge on this forum and how active it is. I really think I'm going to like it here.
graysalchemy said:Sorry If I was a bit cutting before but we see to many smart alecs on here who are trying to reinvent the wheel, it gets a little tiresome. This forum is a wealth of knowledge with numerous professional brewers and some extremely knowledgeable and experienced homebrewers, all willing to pass on their knowledge.
So basically read listen and learn we are friendly bunch who want to help new people in our chosen vocation.
:thumb: :thumb:
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