Thanks "Silver...", things like that are always better coming from someone else and not me
<- loon-ey! ... hoy, shutup you.
So in figuring out my own nonsense I try to look up an SG table for CaCl2 "brines". Surprisingly difficult, but this seemed okay:
https://www.oxy.com/OurBusinesses/Chemi ... -01791.pdf, Table 3a. Hopefully someone can do better than that? But the relevant bit was:
- Capture.JPG (19.87 KiB) Viewed 2925 times
Next was calibrate that ancient hydrometer with a known sugar solution … crikey, can't be bothered! Like many other home-brewers I have cheapo Chinese "jeweler's" scales that can weigh 100g at 0.01g resolution, and happen to have a 25ml measuring cylinder, so:
Subtract weight of cylinder, I could use "tare" but I'm not quick enough to beat the "time-out", and multiply by 4 to pretend I have 100ml and (just need to lookup my book "Mathematics for the Criminally Insane" … ah, here we are) jiggle the decimal point so it looks right, and the result:
1.000
Well it was water in the photo! For the solution I prepared it came out 1.072. So that CaCl2 of mine has absorbed a bit of water and my old hydrometer can go in the bin. I've an 8% solution. I decide there's not much point following "Silver..'s" post and correcting the gravity, 'cos his spreadsheet handles the difference easily. I put "8%" in BW too … Flip, using CaCl2 solutions in Bru'n Water is not so easy, we're still measuring out the solution in grams, not mls, for a start … one up for MME!
FOOTNOTE:
That SG technique comes from memories of school. If you've got scales that weigh fractions of a gram, as many of us have (for weighing brewing salts), that method is
miles better than using old-fashioned, fragile hydrometers! Doesn't need conversion tables like refractometers either. I remember you'd use small volumetric flasks (£2-3) instead of a measuring cylinder, or made for purpose "pyknometers" (okay, maybe £20) or "hubbard bottles" - The last two are great if your sight isn't up to reading to the "meniscus".
The message is clear:
Stop using poxy, old-fashioned and completely un-necessary hydrometers!