fwd mhbac Water Treatment DIY

Some detailed notes on the treatment of well water (hard water) for brewing from our friends in Mad-Town. ----- Forwarded message from Mark Garthwaite <mgarth(a)primate.wisc.edu> ----- To: beer(a)mhbac.org From: Mark Garthwaite <mgarth(a)primate.wisc.edu> Subject: [MHBAC]: Treating Mt. Horeb Water with Slaked Lime Date: Mon, 21 Aug 2006 13:11:11 -0500 More than you may want to know but I'll lay it all out and you can keep it for future reference or go back to your regularly scheduled IPA. I'm posting the nuts and bolts of how the information was processed in case anyone out there is crazy enough to care. I've also attached a spreadsheet with a calculator for coming up with what you need to know without having to understand it. Please note that this is NOT critical to understand if you want to make good beer. Don't obsess over it and realize that the actual treatment is much much easier than I'm making it sound. Also note that calculated and averaged values will not be perfectly accurate but will get you in the ballpark. For those who just want to skip to the "answer" without all of the gory details, here's the bottom line for treating Mt. Horeb water: Adding 229 mg/L slaked lime to half of the water you're treating, mixing well, and then adding the rest of the water will pretty much neutralize the alkalinity of your Mt. Horeb water and knock the bicarbonate down to about 50 ppm which is the best you can expect. If you really want to knock out as much bicarbonate as possible, add about 100 mg/L of CaCl2 AND 100 mg/L of CaSO4 at the same time you add the slaked lime to provide more Ca++ ions to do the job and leave some residual Ca++ for happy enzymes. NOTE: For example, if you're treating 10 gallons of brewing water (3.785 Liters = 1 gallon) or 10 x 3.785 = 37.85 Liters, you'd add: 229 mg slaked lime x 37.85 Liters of water = 8667 mg slaked lime which is 8.667 grams of slaked lime. (For extra effective measures, add 3.785 grams of CaCl2 and 3.785 grams of CaSO4 at the same time) Add 8.667 grams of slaked lime to half (5 gallons) of the water, mix well, let precipitate settle, transfer liquid to another vessel, and add the other half (5 gallons) of water to the treated half of water. You'll get more precipitate and you want to let it settle and decant the water for use in brewing. All of this should be done the night before brewing to get the best results. The messy, gory details: I used the data Ted obtained and just made averages of the relevant info. If I wanted to verify alkalinity I would titrate 100 mL of tap water with 0.1N HCl until it reached pH 4.3. The number of mL of acid added is equal to the milliequivalents per liter (mEq/L) of alkalinity. To get mEq/L from the average alkalinity of 309 ppm from the water report we divide by 60 to get 5.15 mEq/L alkalinity. For every mEq of alkalinity, two mEq of calcium is required to neutralize the bicarbonate. So 5.15 mEq/L x 2 = 10.3 mEq/L of Ca++ required in this case. Multiply that by 20 to get ppm required. (10.3 mEq/L calcium x 20 =206 ppm calcium needed!) Using one of Hubert Hanghofer's formulas (http://netbeer.org/content/ view/13/42/1/1/lang,en/) , multiply your alkalinity in ppm by 0.74/1000 to get the calculated amount of slaked lime required. (309 ppm Alkalinity x 0.74/1000 =0.229 g/L of slaked lime required) This is the amount of slaked lime I would need to use. (Also, 0.229 g = 229 mg for easier calculations below) I want to know how much calcium I have available to complex with the bicarbonates since I know this treatment consumes calcium ions. Given that 40 ppm of Ca++ is equal to 74 mg/L Ca++, 229 mg/L slaked lime divided by 74 mg/L = 3.094 x 40 ppm Ca++ = 123.78 ppm Ca++ added to my water via slaked lime. Then, 123.78 ppm divided by 20 = 6.19 mEq Ca ++ due to the lime addition. We calculated above that we needed 10.3 mEq/L of Ca++ to neutralize the alkalinity. And we determined that the lime addition will add 6.19 mEq/L of Ca++. That means we still need 4.11 mEq/L of Ca++ (10.3 mEq/L - 6.19 mEq/L = 4.11 mEq/L needed) The water report says that the tap water contains an averaged value of 72.64 ppm of Ca++ which we can divide by 20 to get 3.6 mEq/L that is already present in the water. Subtract that from our Ca++ requirement and we're left with a deficit of 2.74 mEq/L Ca++ (10.3 mEq/L needed - 6.19 mEq/L from lime - 3.6 mEq/L from tap = 0.48 mEq/L Ca++ still needed.) Multiply 0.48 mEq/L x 20 = 9.6 ppm of Ca++ needed. For Mt. Horeb's water this isn't much of a deficit so you may not need to supplement with more Calcium ions via CaCl2 or CaSO4. Now, I used Hubert's method of adding all of the calculated amount of lime to half of the water, mix well, and then adding the rest of the water to complete the reaction. When I did this with Madison water my pH of the treated water was 9.9 and I measured the alkalinity as 2.6 mEq/L (or 156 ppm) This showed me that even though I added the calculated amount of lime, I still have some bicarbonate that won't precipitate out of solution because I ran out of calcium ions. You'll run out of calcium with Mt. Horeb water too but not by much. We calculated above that we still needed 0.48 mEq/L of Ca++ ions. So now, I want to figure out how much CaSO4 or CaCl2 I would need to add to make up the deficit. (The following numbers are conversions of readily available data that is usually presented in g/gallon instead of g/L) For CaSO4, 1 gram contributes 230.4 ppm of Ca++/L. We need about 9.6 ppm Ca++ which means we need: 9.6 ppm divided by 230.4 ppm = 0.042 g/ L of CaSO4. *Remember that you'd also be adding sulfate ions as well when using this salt* For CaCl2, 1 gram contributes 270.3 ppm of Ca++/L. We need about 9.6 ppm which means we need: 9.6 ppm divided by 270.3 ppm = 0.036 g/L of CaCl2. *Remember that you'd also be adding chloride ions as well when using this salt.* I prefer to have some Ca++ left over after my treatments to assist with dropping mash pH and making enzymes happy so I would suggest a treatment with 200 mg/L of CaCl2 which contributes 54 ppm/L Ca++. We had a deficit of 9.6 ppm so this treatment results in 54 ppm/L - 9.6 ppm/L = 44.4 ppm Ca++ left over in my treated water. (This is above the amount of Ca++ I need but I know I'm going to have some alkalinity left over that I won't be able to remove with lime so I'll need the extra Ca++ in the mash later). ----- End forwarded message ----- -- ------------------------------ * * Dr. James Lee Ellingson, Adjunct Professor jellings(a)me.umn.edu * * University of Minnesota, tel: 651/645-0753 fax 651 XXX XXXX * * Great Lakes Brewing News, 1569 Laurel Ave., St. Paul, MN 55104 *