ph is .3 lower than water calc

Discussion in 'General Brewing Discussions' started by jay3847, Oct 15, 2018.

  1. jay3847

    jay3847 Member

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    I just brewed a milk stout and have had success with hitting my target ph with BIAB. Unfortunately, I am doing batch sparge equal runnings right now as a way of learning a new skill and the ph is way low compared to the estimate in Brewersfriend. It started 5.0 low and then slow rose to 5.15 instead of the 5.47 I was targeting.

    I double-checked my work, my grist info and also the water source report (crystal geyser). It seems like I would have had to put in triple the amount of lactic acid (which I didn't) to make such a big difference. And, I did recalibrate my Milwaukee meter.

    Here's the grain bill..
    Amount Fermentable PPG °L Bill %
    5.5 lb United Kingdom - Maris Otter Pale 38 3.75 79.1%
    2.4 oz American - Caramel / Crystal 40L 34 40 2.2%
    7.2 oz American - Caramel / Crystal 60L 34 60 6.5%
    1.2 oz American - Caramel / Crystal 90L 33 90 1.1%
    3 oz United Kingdom - Black Patent 27 525 2.7%
    3.5 oz Lactose (Milk Sugar) - (late addition) 41 1 3.1%
    6 oz German - Carafa II 32 425 5.4%

    I added the water adjustments..
    2 g Calcium Chloride Water Agt Mash 1 hr.
    0.5 g Epsom Salt Water Agt Mash 1 hr.
    2 g Gypsum Water Agt Mash 1 hr.
    2 g Baking Soda Water Agt Mash 1 hr.
    0.5 g Slaked Lime Water Agt Mash 1 hr.
    2 ml Lactic acid Water Agt Mash 1 hr.

    Any suggestions on what I can look at discover where I went wrong in the calculations or my process?
     
  2. oliver

    oliver Well-Known Member

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    what are your water volumes? the calculator very much takes that into account, and the source water is very important as well.
     
  3. Yooper

    Yooper Administrator
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    You should never add alkali and acid, as they cancel each other out. Please check the water volumes to make sure you have the water calculator set to such a thin mash.
     
  4. jay3847

    jay3847 Member

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    #4 jay3847, Oct 15, 2018
    Last edited: Oct 16, 2018
    Lots of reading later......

    At the heart of my question is when and how to add salt additions.

    1) I need to hit mash ph, whatever mash technique I am using, and I want 50ppm of calcium. So, I need to add the calcium to mash plus adjust the ph from there with acidulated malt or some such.
    2) Mash technique and thickness affect this, so I need to plan carefully with how much water I add and when.
    3) If I want to add salts for flavor, I'll add those to the kettle.

    Am I stating this correctly?
     
  5. Yooper

    Yooper Administrator
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    Yep- you got it! For number 2, mash thickness affects it but not hugely. Doing BIAB however means more water than the typical 1-2 quarts per pound done by traditional mashing methods so if you're using water with a high bicarbonate content, the mash pH may be higher than with traditional methods.

    Have you seen the article on "Basic Brewing Water"? It's in three parts- here is part 1: https://www.brewersfriend.com/2017/11/19/brewing-water-basics-part-1/
     
  6. jay3847

    jay3847 Member

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    Thanks, Yooper. I'll reread that with a bit more understanding now...... and I might need to re-brew that stout.
     
  7. Nosybear

    Nosybear Well-Known Member

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    0.3 points... DidYou take the reading while the mash was still hot? Hot mash reads about 0.3 points lower than cool mash. Can go either way if the recipe creator reads mash pH hot and you read cool.
     
  8. jay3847

    jay3847 Member

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    I test hot and cold. I did a 30 min and 60 min reading on the mash using the Milwaukee 102. I would take a small sample and cool it a bit and then test. The cold sample was end of the day after racking to the fermenter. All read basically 5.1.

    I'm going to get some grain and do some tests to compare against brewersfriend calculated ph.
     
  9. Nosybear

    Nosybear Well-Known Member

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    Are you using tap water? It can vary significantly from the water report and cause "off" pH readings.
     

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