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Was - Another Winemaking Calculator
"frederick ploegman" > wrote in message ... > 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 > > Frederick > > > > "frederick ploegman" > wrote in message > ... >> Steve, Pp, et al >> >> 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 >> >> Frederick >> >> >> "pp" > wrote in message >> ups.com... >>> 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: http://www.brsquared.org/wine/ >>> 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... >>> >>> Pp >>> >>> >>> On Feb 19, 6:17 pm, "Steve Gross" <gross**at**pdq**dot**net> wrote: >>>> 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 >>>> (http://web2.airmail.net/sgross/fermc...c_alcohol.html) 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. >>>> >>>> Steve >>>> >>> >> >> > > |
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