It's a Java applet and you'll need to install the Java Plugin
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to run it.
This started out as a project for a Java class I took, and it developed into something I find useful in my winemaking, so I've decided to document and share it. The accompanying "Calculation Details" pages document all of the formulas and assumptions in the calculations. I've tried to validate the calculations with published tables and other calculators out there, but if you see any strange results be sure to let me know.
It should run on any platform, but I've only tested it on Windows XP. I'd appreciate it if any Linux or Mac users out there could give it a try. Any feedback would be appreciated.
I have a barrel that I needed to add sulphite to, and the calculator nailed it! Love that you can specify PotMet, choose crystal, or solution and concentration to calculate qty needed.
I'm a Mac user on Firefox and it worked great after I 'allowed' Java scripting on that page.
Thanks Steve. I particularly appreciate that you've revealed the formulas underlying the calculations - that's often not the case. In terms of the actual calculations, you'll most likely get some flak for PA - that's a hot button topic for many people. I've never seen that Balling formula - a quick Google search came up with some references but all in the context of beer?
Don't talk to me about PA! At least Steve's calculated PA will be more accurate than my own triple-scale hydrometer's version! Grrr. Don't get me started ;)
Thanks for that - it works fine on Safari on my Mac. My only complaint is that I didn't see this until this morning (Tuesday AM - Australian time) and I can't really blame you for that, can I. : - )
When we crushed on Sunday, we did our usual back of an old envelope calculation for sulphite additions and came up with 220 grams for 800 litres of wine - D'oh - it should have been 22 g, just like your calculator said.
Thanks, EnoNut, for testing it on your Mac. I'm glad it's working for you and potentially for other Mac users.
I have a barrel that I needed to add sulphite to, and the calculator nailed it! Love that you can specify PotMet, choose crystal, or solution and concentration to calculate qty needed.
I'm a Mac user on Firefox and it worked great after I 'allowed' Java scripting on that page.
Okay, I didn't mean to start a fight! But in answer to Pp's comment about the Balling formula, yes, there don't seem to be any references to its use in the context of wine, at least on the web. But when I tested it, the results were remakably similar to the Duncan & Acton formula. And when you compare equations (5) and (8) on my documentation page
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you'll see that both formulas have a very similar form. I found these comparisons somewhat compelling, so I included both formulas in the calculator.
No fight here. I noticed the 2 results closely correlate but that could just mean one formula could be derived from the other the real test is judging the computed results against measured values. The practical problem with this is we don't seem to have ready access to measured alcohol values so it's hard to support any result well.
Some people discard D&A's work because they argue considering the final gravity is plain wrong because anything that goes under sg 1.0 is just the effect of alcohol created from the sugar (which is captured by initial s.g. value). That would also apply to Balling's formula. This is more pronounced for wines where often the final s.g. can get to 0.990 for dry wines.
Personally, I think that argument is faulty because it ignores how the formula was designed - it's just as easy to base the PA values solely on the initial s.g. as it is to base them on the difference between final and initial s.g. The latter does not artifically "add sugar that's not there", it just incorporates the fact that the sugar progressively changes into alcohol and bases the calculation on that. The results will not completely agree but it's just an estimate anyway because the actual alcohol depends on many factors that cannot really be measured in practice.
That said, based on the s.g. values of the grapes and juice we routinely get from California these days, I think the D&A formula exagerates the PA values by about 0.5-1% of abv. Again, this is imprecise as it's based on taste comparisons of my wines with commercial wines with stated alcohol value, but it works for me and that's really what matters in the end ;).
You might want to check out this page:
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in the Calcs/Info section, it has some other formulas from the literature. Actaully, given that you're already showing 2 different values anyway, it might be of real value to collect all the different formulas you can get hands on and add those to the applet, kind of like what Ben has in his table but more extensive. That would give people a full range of PA results comparison in one place; I think that'd be really useful.
One final note on the subject of precision - I think all calculations should be round up to give the PA values in 0.5% increments. Anything more than that gives a false impression that the computed value is the exact amount of alcohol in the wine, which is at odds of what the formulas can really do.
Sorry, I've made this longer than I wanted - I keep promising myself I won't get involved in these debates anymore but it doesn't seem to work...
Ha ha, I don't think there can be a logical fight when there are several ways to calculate it. I just mean that after my thread about far out my hydrometer's PA scale was, a good general guide in the calculator was a good thing, hence the wink :)
I had to state the same bsquared table as you did Pp to demonstrate just how confused I was about PA and why there weren't absolutes. My PA scale doesn't equate to any of those five either. I wondered what the Scottish makers of my hydrometer were basing their callibration on and couldn't find a scale in agreement with them.
I'm just grateful for the tool, and for opinions and information so generously shared here by the winemaking community.
Thanks for the discussion. I don't disagree with any of the points you make. I especially agree that there's no reason not to include final sg's that are under 1.0 in the alcohol content calculation. It seems to me that only by considering the total sg drop can you really estimate the overall compositional change during fermentation. But I know others out there disagree.
Steve
No fight here. I noticed the 2 results closely correlate but that could just mean one formula could be derived from the other the real test is judging the computed results against measured values. The practical problem with this is we don't seem to have ready access to measured alcohol values so it's hard to support any result well.
Some people discard D&A's work because they argue considering the final gravity is plain wrong because anything that goes under sg 1.0 is just the effect of alcohol created from the sugar (which is captured by initial s.g. value). That would also apply to Balling's formula. This is more pronounced for wines where often the final s.g. can get to 0.990 for dry wines.
Personally, I think that argument is faulty because it ignores how the formula was designed - it's just as easy to base the PA values solely on the initial s.g. as it is to base them on the difference between final and initial s.g. The latter does not artifically "add sugar that's not there", it just incorporates the fact that the sugar progressively changes into alcohol and bases the calculation on that. The results will not completely agree but it's just an estimate anyway because the actual alcohol depends on many factors that cannot really be measured in practice.
That said, based on the s.g. values of the grapes and juice we routinely get from California these days, I think the D&A formula exagerates the PA values by about 0.5-1% of abv. Again, this is imprecise as it's based on taste comparisons of my wines with commercial wines with stated alcohol value, but it works for me and that's really what matters in the end ;).
You might want to check out this page:
formatting link
in the Calcs/Info section, it has some other formulas from the literature. Actaully, given that you're already showing 2 different values anyway, it might be of real value to collect all the different formulas you can get hands on and add those to the applet, kind of like what Ben has in his table but more extensive. That would give people a full range of PA results comparison in one place; I think that'd be really useful.
One final note on the subject of precision - I think all calculations should be round up to give the PA values in 0.5% increments. Anything more than that gives a false impression that the computed value is the exact amount of alcohol in the wine, which is at odds of what the formulas can really do.
Sorry, I've made this longer than I wanted - I keep promising myself I won't get involved in these debates anymore but it doesn't seem to work...
I have found no one who can definatively say which way is right. I include the drop below 1.000 but have been in heated arguements with those who disagree. You could calculate it both ways and report the results as a range.
You won't find references to Balling because it's pretty much replaced by Brix. I have a definitive reference; Polarimetry, Saccharimetry and the Sugars by Bates et al; NBS C440; see page 248.
To make a long story short Balling proposed measuring sucrose by weight but he used an odd temperature reference; 17.5C for the standard solutions. Brix recalculated that scale based on a standard temperature of 20C which is the most common temperature hydrometers are calibrated for. (this was in the mid 1800's.) Beer-makers seem to love obscure scales; they use Plato too and that one is unusual too, it uses that same reference temperature of 17.5 C. I think South Africa may still use Balling.
Potential Alcohol is even less useful than a hydrometer; at best it should be considered a ballpark measurement. Too many variables exist that have nothing to do with density for this measurement to be useful for precise measurements. That said, ballpark is all an amatuer ever needs, we are not taxed on alcohol levels like commercail wineries.
Why not try that "boil off the alcohol" procedure that someone mentioned here earlier. With the alcohol gone and the "before and after" readings restored to direct comparability, any of the old formulas that ignored alcohol completely should then work.
Never tried this myself. Just found it easier to compensate for the alcohol numerically. HTH
Ooops...Nope. With the alcohol gone, seems I would have to add 3 points to the difference in order to get the best estimates when using the "old" formulas (a la CJJ Berry). (eg. to compensate for the 3 point allowance for acid used in the BRIX calculation). These "old" formulas were based on the assumption that the acid and alcohol would cancel eachother which of course isn't true or we would never get readings below 1.000.
FWIW - For dry ferments, no calculation is required because the original PA already tells us how much alcohol the wine will have when (if) all of the sugar gets converted. So - the only time we need to calculate is for RS wines/musts. With sugar, alcohol, and acid all present when the post pitch reading is taken, it is then a matter of sorting out how much influence each one has on the single SG reading we have to work with.
I no longer have my books and my memory sure ain't what it used to be, so I think I better shut up and let you guys figure this out...........HTH
PS - The news reader at my ISP only allows me to read the last 60 days worth of posts. If you are posting replies to threads older than this, I can't read them. Since I think others may be having the same problem, it might be nice if you would start new threads instead. TIA
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