You started a great discussion, and it brought to light measuring/calculating techniques that were new to me (and, I suspect, several others in the forum), with respect to more accurately determining solution properties in the middle of a fermentation.
The issue is not tricking hydrometers and alcoholometers into giving more accurate readings; for our purposes they measure quite accurately. The problem is that both instruments only measure density, specific gravity, and we want to infer all kinds of other information, different
information, from that density value, and we want it to work equally well for sugar washes, wines, rum washes, and grain washes, some very different kinds of fermenting mixtures.
To the extent that I can get my head around it, it appears our best tools for understanding the progress of a fermentation all start with an initial, pre-yeast pitch, specific gravity value or index of refraction, and use the changes in those values to extrapolate the data we seek. If I may use a simile, it's like trying to determine the velocity of a bullet with an instrument that tells us the position of the bullet; if all you know about the bullet is where it is now, you know nothing about its velocity
. If, however, you also know its position at some other time, you can get a pretty good idea of its velocity.
Admittedly, our old technique of measuring density through a fermentation is a little crude, but it can be pretty effective with common, inexpensive instruments. The calculator in the Vinocalc site that Landrover just showed us refines this a lot, using both
density and index of refraction changes to give us approximately the values we seek, but that still starts from initial measurements, and works from the changes in measurements, and requires more expensive instruments.
I acknowledge that brewers, vintners, and distillers used to work with no instruments at all, and got some excellent results, sometimes
. Some of them no doubt built their own instruments, like your nail and straw hydrometer, which was clever (I'm still curious as to why you calibrated it at 90C rather than closer to "room temperature").
I think each of us makes some decision about how much instrumentation we need and will use, and can afford. For instance, I'd love to have a gas chromatograph for exploring flavor compounds in spirits, but at my hobby level that might be silly. If you choose to work with no instruments, that's valid, too. Just know that each of us have good reasons to work at the level that each does, and we have this forum to examine how we might change that level.
So don't be angry with us. You found out what the low-end of instrumentation could do, and also what the high-end (for hobbyists) could do. If that makes us simple question answerers, I'll take that judgment happily.
Zymurgy Bob, a simple potstiller
--- In Distillers@yahoogroups.com, Timothy Smith <timothyc.smith@...> wrote:
> I thought this forum was more than a simple Q&A place. I was not trying to get a
> direct answer as much as hoping that out of the many people that look at this
> Yahoo Group, a few of you might have some tricks that could help out in the way
> of tricking your Hydrometer or Alcometer into giving a more acurate reading in a
> I do not need to spend money on a simple piece of equipment and then 40
> dollars for shipping, just so I can have more gussing to do.
> I really don't need to know the exact numbers in my washes. I don't have a
> problem telling the differance between finished and stuck. +Tried and tru
> recipes have never failed me yet.
> I have all of the instriments I need...