I know what I'm reading in the winemaking-FAQ:

(Start SG - Finish SG) / 0.0074 = % alc

That's easy enough. It's not consistent with what I think I'm
understanding from Pambianchi who calculates down to a finishing SG of
1.00 regardless of the actual value which often is < 1.00.

Which is correct?

The former seems more reasonable to me.

"glad heart" > wrote:
> I know what I'm reading in the winemaking-FAQ:
>
> (Start SG - Finish SG) / 0.0074 = % alc
>
> That's easy enough. It's not consistent with what I think I'm
> understanding from Pambianchi who calculates down to a finishing SG of
> 1.00 regardless of the actual value which often is < 1.00.
>
> Which is correct?
>
> The former seems more reasonable to me.

There are a number of formulae for calculating potential alcohol, and they
are ALL estimates. The tabular values were obtained empirically using
distilled water and sugar in a laboratory. (There are simply too many
variables to do otherwise, and actual results will vary accordingly.) Most,
if not all, formula, are attempts to express "mathematically" what has been
measured empirically.

Here are a few formulae, and summary of their derivation and factors:
http://members.tripod.com/~BRotter/C...o/HydSugAl.htm. I suggest you use
whichever one is easiest (or most sensible) to you.

Great link. Much obliged.

There are all sort of formula, some are very complex and others overly
simple. I can give you the formulae I use which is derived from Duncan and
Acton's "Progressive Winemaking" and checked against the basic PA tables
that are out there (most of which will lead you astray). It is

% Alcohol = (Go - Gf) / F

Where Go is original gravity and Gf is final gravity and gravity is defined
as

G = (SG-1)*1000.


And F is a value that takes into account the non fermentable solids in the
must and is defined

F = 7.75 - 3*(Go - 7) / 800

Email me directly if you would like a write up on this.

Ray

"glad heart" > wrote in message
om...
> I know what I'm reading in the winemaking-FAQ:
>
> (Start SG - Finish SG) / 0.0074 = % alc
>
> That's easy enough. It's not consistent with what I think I'm
> understanding from Pambianchi who calculates down to a finishing SG of
> 1.00 regardless of the actual value which often is < 1.00.
>
> Which is correct?
>
> The former seems more reasonable to me.

On 11/13/03 8:22 AM, in article
, "glad heart"
> wrote:

> I know what I'm reading in the winemaking-FAQ:
>
> (Start SG - Finish SG) / 0.0074 = % alc
>
> That's easy enough. It's not consistent with what I think I'm
> understanding from Pambianchi who calculates down to a finishing SG of
> 1.00 regardless of the actual value which often is < 1.00.
>
> Which is correct?
>
> The former seems more reasonable to me.

I generally use the latter formula as it correlates with the potential
alcohol scale on my hydrometer.

--
Greg Cook
http://homepage.mac.com/gregcook/Wine

(remove spamblocker from my email)