Note: this post has been corrected for bad math. Pusser's was also tested but this was invalid (for now) as it is not a 40% rum.
Some time ago Sleepy offered to settle the whole damn sugar matter by graciously offering to buy a refractometer and get 'er done. This was I thought, a brilliant idea and offer for not just a few reasons. A meter could be had for around $20 (I ordered one for $17 delivered), these were generally very accurate (within 1/10 of one Brix), quick (took only 30 seconds), automatically adjusted for standard temperature, 20C and best of all, only required a few drops of rum. In sum...
The perfect meter for any idiot, and especially this one. Usable by anyone, anywhere with good readings almost guaranteed. Wow! The way these work is this: a few drops of liquid are placed on the glass and covered. Ambient light passes through the liquid and is "bent". If sugar is present the light is "bent" more and voila! You get a higher reading in "Brix" which refers to the amount of solids in the liquid. Allegedly fast, accurate and easy peasy!
But there's always a spoil sport, and this time it was no less than our good friend RS, who pointed out that sadly, these meters are calibrated to determine Brix/sugar compared to distilled water. Because rums are normally 40% alcohol or so, the meter would calculate a Brix that was way too high (because alcohol has a lower specific gravity than water). Thus any readings would not be reliable. "Nonsensical" he said.
But I argued, couldn't I create our own table by taking reading of a test solution of 40% alcohol in distilled water, then add sugar in increasing amounts, take readings and produce our own graph, thus converting the "nonsensical" numbers to actual amounts? Is this possible I asked? Although my theory drew large guffaws, after a delay RS got back to me and stated "Yes, but it would only be good for 40% rums. You'd have to make a different table for other proofs.".
In other words, I could use a refractometer, but only after creating a table for 40% rums. Because I liked the ease and potential accuracy of the meter, I ordered one anyway, which was just delivered. Since most rums are 40% anyway, I believed it would be worth creating at least a 40% table.
Was the receipt an exciting experience?
You bet. There's nothing like a new toy, especially one that will find sugar in rum. No I didn't create a table - but - I just had to see how accurate and easy it might be to use. Accordingly I tested two rums of great interest:
Seales 10, and of course, - a old bottle of Z23 (purchased over 8 years ago and still using 23 "anos" on the bottle). I took a few readings and discovered the following:
- 1. The meter was extremely consistent and could easily and repeatedly be read to 1/10 of one Brix.
2. The results:
- Seales: 14.4
Zee 23: 17.9 or 18.0
- Seales: 14.4
Since we know the old Z-23 probably had around 40g of sugar, and since the refractometer read 3.5 Brix higher than the Seales control rum, a rough estimate is that each point of additional Brix would translate into about 11.4 grams of sugar per liter.
Flat Ass Bottom Line
This is incredible news. It worked!
With no calibration, no test runs, and no tables - by simply using Seale's 10 as a control, the Brix calculated for a very old Z-23 was remarkably close to the actual amounts reported by the Finnish/Swedes for a current Z-23. If this can be repeated for other rums with known sugar levels, this may well eliminate the need to create a table/graph. The acid test will be comparing the refractometer along with the hydrometer in testing of 40% test solutions (from zero to 50 grams of sugar).
By next week both methods, but surely that using the hydrometer should be ready to go...
