Quick Bru'nWater Question

[WiscBrewer]

I'm trying to use a Calcium Chloride solution for the first time and want to make sure I have this right. My solution has a measured SG of 1.090. According to Bru'nWater's calculator, this equals 9.9 %w/w. On the adjustment summary page, it indicates I need 14 grams of solution for 8 gallons of strike water. So....that's literally what's needed? I'm weighing to get 14 grams of solution, correct?

 

[jerbrew]

As long as you have the the cell for CaCl2 form marked liquid and the correct %w/w below it then yes. You measure the mass of whatever form of CaCl2 you have. in this case 14g of 9.9%w/w solution.

 

[mabrungard]

Sounds like you are using it correctly. Recognize that the w/w solution means that X% of the liquid mass is actually anhydrous CaCl2. So adding 14 g of 10% solution is the same as adding 1.4 g of anhydrous CaCl2.

My caution to you is, how did you determine that solution's SG? I'm hoping that you tared your volumetric container and weighed it with the solution and then divided by the measured volume. That can be more accurate than a hydrometer if the volumetric container is accurate.

 

[WiscBrewer]

Sounds like you are using it correctly. Recognize that the w/w solution means that X% of the liquid mass is actually anhydrous CaCl2. So adding 14 g of 10% solution is the same as adding 1.4 g of anhydrous CaCl2.

My caution to you is, how did you determine that solution's SG? I'm hoping that you tared your volumetric container and weighed it with the solution and then divided by the measured volume. That can be more accurate than a hydrometer if the volumetric container is accurate.

This stuff makes my head hurt. OK, I got my initial SG with a plain old hydrometer. I then used your procedure and found that 10ml of solution weighs 10.69 grams. The figure I should use in the spreadsheet, then, is 1.069?

Thank you for the help!

 

[ajdelange]

Just calculate the grams of CaCl2.0H2O needed and then use the formula in the sticky
g/L = -684.57 + 175.12*SG + 509.45*SG*SG
to figure out how many grams of CaCl2.0H2O are in a liter of your solution. From there it is a piece of cake to figure out how many mL of solution you need and there is no need to weigh anything.