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-   -   Add gypsum to sparge, or directly to kettle? (http://www.homebrewtalk.com/f128/add-gypsum-sparge-directly-kettle-354113/)

scone 09-13-2012 05:07 PM

Add gypsum to sparge, or directly to kettle?
 
I can't seem to find the answer to this although I feel like it must have been asked. I'm using the bru'n water spreadsheet and trying to wrap my mind around the chemistry involved. It is suggesting a bit of sparge water acidification (to the tune of .47 tsp/gallon) given my water chemistry as reported on the city water quality website (http://www.austintexas.gov/sites/default/files/files/Water/WaterQualityReports2012/wqs_2q2012.pdf). This is fine and dandy, but I am also a bit low on calcium, so playing with the Water Adjustment page it looks like I can do 1.0 g/gallon gypsum to compensate (which additionally helps push my predicted mash pH into a good place).

The spreadsheet seems to imply that I should treat my mash AND sparge water with gypsum, but wouldn't this mess with the alkalinity of the sparge water? The Sparge Acidification page doesn't seem to consider my altered water chemistry, only the water chemistry I input on the first page. So my question: should I hold back the gypsum addition from the sparge water and just add it to the kettle? Does it matter?. I'm already adjusting the sparge water using phosphoric acid, so it seems like adding gypsum as well (without knowing its effect on the pH is a bad idea).

In summary, my plan is to:
Use phosphoric acid in the sparge water to hit the right pH
Use gypsum in the mash to adjust mash pH and add calcium to the water

afr0byte 09-13-2012 05:22 PM

Quote:

Originally Posted by scone (Post 4410165)
I can't seem to find the answer to this although I feel like it must have been asked. I'm using the bru'n water spreadsheet and trying to wrap my mind around the chemistry involved. It is suggesting a bit of sparge water acidification (to the tune of .47 tsp/gallon) given my water chemistry as reported on the city water quality website (http://www.austintexas.gov/sites/default/files/files/Water/WaterQualityReports2012/wqs_2q2012.pdf). This is fine and dandy, but I am also a bit low on calcium, so playing with the Water Adjustment page it looks like I can do 1.0 g/gallon gypsum to compensate (which additionally helps push my predicted mash pH into a good place).

The spreadsheet seems to imply that I should treat my mash AND sparge water with gypsum, but wouldn't this mess with the alkalinity of the sparge water? The Sparge Acidification page doesn't seem to consider my altered water chemistry, only the water chemistry I input on the first page. So my question: should I hold back the gypsum addition from the sparge water and just add it to the kettle? Does it matter?. I'm already adjusting the sparge water using phosphoric acid, so it seems like adding gypsum as well (without knowing its effect on the pH is a bad idea).

In summary, my plan is to:
Use phosphoric acid in the sparge water to hit the right pH
Use gypsum in the mash to adjust mash pH and add calcium to the water

Go ahead and add the gypsum. It doesn't add alkalinity.

scone 09-13-2012 05:26 PM

Quote:

Originally Posted by afr0byte (Post 4410235)
Go ahead and add the gypsum. It doesn't add alkalinity.

Sweet. Thanks afr0byte. :mug:

helibrewer 09-13-2012 05:40 PM

It's chalk you want to avoid in the sparge and mash.

cooper 09-13-2012 05:46 PM

And depending on what your sulfate level is already, you might want to skip the gypsum and add a tsp of Calcium Chloride per 5 gallon of water to be treated.

Most of the time, accentuating the Malt profile results in a more enjoyable beer and that's what CaCL does (but remember more is not always better). Most beers need very little gypsum and that's only in really hop-accentuated IPAs, but that's just my two cents. This advice is along the lines of what Aj recommends and I've had a lot of success following his advice.

mabrungard 09-13-2012 05:49 PM

If your goal is to produce a certain level of calcium and sulfate in your finished wort, then adding a dose of gypsum to account for the sparge water volume is required. You don't have to add that gypsum to the sparge water, but can add that dose directly to the kettle if you prefer. As pointed out above, gypsum does not add alkalinity, so its OK to add to the sparge water.

As you noted, adding the gypsum to the mash is helpful for helping lower the mash pH in addition to its other calcium effects. Do add it there.

By the way, that seems like a lot of acid if it was 88% lactic. But I see that you are using phosphoric and the strength is not denoted. Given that Austin water is lime softened and the alkalinity is moderate, I'm assuming you are using 10% phosphoric and not 85%. If that is the case, then that quantity of acid in the sparging water is not surprising.

scone 09-13-2012 05:53 PM

My water has 47.3 ppm sulfate to 48 ppm chloride (after treatment with kmeta to remove chloramines, assuming the additions suggested on the bru'n water homepage). I guess maybe I should do a 1:1 gypsum and CaCl addition instead of pure gypsum to keep them balanced? Which begs the question, can I also put CaCl in the sparge water without worrying about it's effect on sparge pH?

scone 09-13-2012 05:54 PM

Quote:

Originally Posted by mabrungard (Post 4410341)
If your goal is to produce a certain level of calcium and sulfate in your finished wort, then adding a dose of gypsum to account for the sparge water volume is required. You don't have to add that gypsum to the sparge water, but can add that dose directly to the kettle if you prefer. As pointed out above, gypsum does not add alkalinity, so its OK to add to the sparge water.

As you noted, adding the gypsum to the mash is helpful for helping lower the mash pH in addition to its other calcium effects. Do add it there.

By the way, that seems like a lot of acid if it was 88% lactic. But I see that you are using phosphoric and the strength is not denoted. Given that Austin water is lime softened and the alkalinity is moderate, I'm assuming you are using 10% phosphoric and not 85%. If that is the case, then that quantity of acid in the sparging water is not surprising.

Thanks! And yes, I should have specified. I'm using 10% phosphoric acid.

cooper 09-13-2012 06:45 PM

Quote:

Originally Posted by scone (Post 4410354)
My water has 47.3 ppm sulfate to 48 ppm chloride (after treatment with kmeta to remove chloramines, assuming the additions suggested on the bru'n water homepage). I guess maybe I should do a 1:1 gypsum and CaCl addition instead of pure gypsum to keep them balanced? Which begs the question, can I also put CaCl in the sparge water without worrying about it's effect on sparge pH?

I would go with only the CaCL since your sulfate level is already close to 50ppm. And most people treat both mash and sparge water together, so no need to treat separately

scone 09-13-2012 11:02 PM

Quote:

Originally Posted by cooper (Post 4410528)
I would go with only the CaCL since your sulfate level is already close to 50ppm. And most people treat both mash and sparge water together, so no need to treat separately

Unfortunately unless I dilute with distilled water, the only way for me to reach 40+ppm Ca is to use both gypsum and calcium chloride (if I try to just use CaCl2 my chloride goes above 100ppm, which the spreadsheet tells me is baaad.) :D

If I do .3 g./gal. gypsum and .4 g./gal. CaCl2 I get
Ca Ma Na sulfate chloride
58.2 18.0 24.4 91.5 99.0

with a comfy buffer on Ca levels, but pushing the upper limits on what's recommended for sulfate and chloride both. Hmm, maybe I should consider diluting with distilled water, it's just kind of expensive! :mad:

By the way, mabrungard, thanks for making the spreadsheet. It's awesome! :tank:


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