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Posted to rec.crafts.winemaking
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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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