Brix vs SG

I don't know which method you should use. I do know that I make Mead and need to know the Brix of various ingredients so that I can estimate OG which I measure with a hydrometer.

One day digital hydrometers will be available so inexpensively that there will be a hydrometer on every fermenter.

Dick

FWIW: I use a refractometer in the vineyard to get a reading of sugars. At harvest, I use both a refractometer and a hydrometer and adjust both for temperature. If there is much discrepancy I do it all over again and try to figure out why. From then on, I use only the hydrometer.

Unless you are in the UK where triple scale hydrometers made after

1983 seem to feature a different version of PA to anyone elses heh heh...

Wayne

Hmmmm. First. Refractometers are the preferred tool of grape growers and grape buyers when the_only_requirement is to evaluate the sugar content of grapes. For everything else hydrometers are used.

As to Brix vs SG, it's not a matter of one or the other but rather a progression. SG is used to estimate sugars. This estimate of sugar is then expressed using Brix as the unit of measure. Make sense ?? Thereafter, _ALL_ calculations are based on this estimate of sugar. Folks who work mostly with grapes usually prefer to do their calculations using Brix as their unit of measure while others often prefer to use SG. It's mostly a matter of choice.

Home winemakers and those who work with non grape wines mostly prefer to work with mulit-scale hydrometers because most of the calculations were done for us when they calibrated these hydrometers. IOW - there is no need to calculate Brix because there is already a Brix scale on the hydrometer. And there is no need to calculate PA because there is already a scale for this on the hydrometer. This makes it all very easy. And it makes it easy to understand the relationships between these things by simply cross referencing back and forth between the scales without having to do all the calculations and then comparing the results.

HTMS

Frederick

I think the only change was to the temp standard used for calibration. I still have the older ones that used 60f as the standard. I think most of the newer ones use 68f as the standard. The standard used should be printed on the each hydrometer. Temp compensate and you should end up with the same numbers.

That is a sensible deduction. However, the hydrometer one I inherited from my father - which matched the scale commonly used in the US - was calibrated to the same temperature as my current triple scale which doesn't match any PA system anyone else seems to use :D

I am sure you are right in general though Frederick!

Jim

Hmmmm...The ones I have also state that they are specifically designed for use in beer and winemaking. Yours ??

Yes they say "wine or beer" at the top of the hydrometer. Both were made by Peter Stevenson Ltd (made in Scotland). Sadly I have broken the one which used the same PA scale as the American system (and which was made I think actually in 1976) The current model was copyrighted in 1983 and is the same one I can still buy from my winemaking shop. They were both made for beer and winemaking. Curious isn't it. I once tested the PA scale of the two side by side and in some areas it was wildly different. I think the differences are recorded somewhere on the group though I can't find them at the moment.

Jim

Sorry for the poor composition but here are the markings at the high end of my hydrometer:

They don't tally at all with any of the 5 PA sclaes on the chart from brsquared.org

That's why I think it's weird...

Jim

Wellll.....It uses 20C (68f) for it's temp standard while mine uses

15.56C (60f), but IIRC (I sometimes don't) that is slightly less than 1 SG to compensate (0.9 ??). I don't see any balling or brix scale on that thing and wwithout it there is no way I can "back engineer" what they may have done. Which pretty much leaves me clueless at this point. Sorry.........Maybe the maker would answer your questions........

Frederick

PS - One thing for sure. It's hard to discuss things unless everyone sings from the same sheet of music. ;o)

Jim

Please excuse me if I ramble. This one just keeps rattling around in my head, nagging at me.

1. Both hydrometers were made by the same company.
2. No great revelations occured in 1983 that would justify such a radical change.
3. What_did_ occur in that time frame was the UK converting from IMP to Metric measure (IIRC ??)
4. I think maybe someone at that company screwed up the conversion and it has taken 25 years for someone to come along to discover that error. (remember, both were made by the same company)
5. Try getting a hydrometer made by a different manufacturer and see if it doesn't conform to the normal convention........

Just the ramblings of one old man. Easily ignored if they prove to be wrong. HTH

Frederick

Hi Frederick.

It occurs to me that you have hit the nail on the head! I have tried to get another brand of hydrometer - because I wanted one that matched the common US interpretations but none of the 4 shops on the high street and online sell one by a different manufacturer. I may be able to source one online. I will have a crack at getting a 360 view of the current hydrometer and will scan in my current to show the clear variation.

I feel certain that if more people in the UK went by PA rather than SG they would have modified their markings years ago ;)

Thanks again for the rationale!

Jim

OK, I have taken some new shots of the new hydrometer (on the right) and scanned and laid the old hydrometer (on the left) as best as I can fit it to the same markings. There are a couple of inconsistencies with what I said before I th ink. Firstly the old hydrometer is from

1973 (the second being 1983) and second the calibration temperature on the old hydrometer is 21C (70F) whereas on the new hydrometer it is 20C (68F).

You can see that by the time you are over 1.090 the scales differ greatly. Also the PA interpretation is rather different. Fair enough, as Luc reiterated there are many ways of interpreting PA. However, interesting that one company would change its interpretation, scale and calibration. It would make sense that it was due to computational differences as the UK moved from Imperial to Metric. This has interested me for a long time!

Hope that provides some food for thought either way Frederick.

Regards, Jim

p.s. I decided to scale the old hydrometer size to match the new one. At first I scaled so that 0.090 matched and 1.20 matched. Then decided that it was more likely that the inconsistencies between the two hydrometers would arise at greater extremes of density/PA so I scaled to match as many SG graduations as I could. If I have introduced greater error in the process this should be noted.

The old one conforms to the normal convention that I have always used. Seems the problem with the new one lies in the "Approximate Sugar" column. And, since PA is based on the estimate of sugar, the PA column is also wrong. Guess you could use the new one to take SG readings and then use the old chart to work from. Seems to me that it would just be easier to get a hydrometer from another manufacturer though. HTH

Frederick

Yes very interesting...

I work from SG anyway so it doesn't make much odds, its just handy for an 'at a glance' reference seeing as it is supposed to be a triple scale! I found it interesting also that neither hydrometers are marked below a PA of 5 anyway...

Thanks for having a think anyway Frederick, much obliged,

Jim

Jim, I'm a metrologist but can't open those pictures, if you email them to me I can give it a look; I used to calibrate hydrometers... I use S.G. exclusively but it's a personal preference.

Joe