Originally Posted by Inhiding
When I used a hydro it lifted the hydro right out of the tube. I will call the wine supply place and ask what the concentration is for future use.
That means it is concentrated. Is it syrupy?
You can still assay it by diluting but as things are by weight you must dilute by weight. If you weigh out 3 oz of the acid and add 9 oz of water you will dilute by approximately 4:1. Note these are not fluid oz but oz measured on a scale. 88% acid would fall, after dilution by this much, into the range where it can be measured by a hydrometer that only goes up to 1.170. The concentration of the original (undiluted) acid is
conc_orig = conc_dil*(1 + acid_wt/added_water_wt)/(1 + conc_dil/100)
Concentrations are in %. Thus if you add 9 oz of water to 3 oz of acid and measure SG = 1.100 corresponding to about 17.5% for the dilution the original acid is
17.5*(1 + 3)/(1 - .175) = 84.8%
It is also possible to use volume dilution which is much easier to do but you would need a spreadsheet to solve for the original acid strength. For example if you took 50 cc of the stock acid and added 100 cc of water and found that mix to have SG = 1.140 the strength of the stock is 88%. The spreadsheet is very simple (12 cells) and I can make it available to anyone interested.