Help! My mash keeps stalling.

[NYB Distilling]

  My fermentation keeps shutting down early and I can’t get it going again.  I made three double batches no problem.  I moved and change my water source and my first batch was fine.  Water quality test strips look good.

  My mash bill is 11# of milled corn, 2# milled, malted rye and 2# milled, malted high diastatic power barley; total of 15# grain, 5 gallons water.  I add 2 teaspoon gypsum and adjust pH to 5.2 to 5.7 before adding corn.  I add two tablespoons of Alpha Amylase at 148-150 degrees and steep for an hour.  I add two teaspoons Gluco Amylase at 90-100 degrees and steep for another hour.  I throw in the malted grains at 90-95 degrees and steep overnight. 

  I use 10 grams of FermPro927 (brand new and kept in refrigerator) and 2.5 Tablespoons of Fermax Nutrient at 85-90 degrees and maintain that temperature range with warming matts through the fermentation.  Initial pH is 5.2 to 5.7 and I keep the pH above 4.0 by hanging oystershells and adding about eight Tablespoons of calcium carbonate over the first three days. I have never been able to get it above 4.4, but FermPro tells me anything 3.6 to 6.0 should be fine.

  The first double batch doth stalled out at about1.010, the second at 1.016 and 1.020.  I couldn’t taste much sweetness and an extra shot of yeast and nutrient didn’t wake it up.  Yields have been about 75% of the first double batch with this same water/yeast combination.  The first (good) batch came off at 1.001; it was down from the day before and still bubbling, I only took it off because I had to travel the next day.

  What to try next???

[smokinjoe]

Thank you for stopping by, and welcome to SB.

[flahute]

1 hour ago, NYB Distilling said:

  My fermentation keeps shutting down early and I can’t get it going again.  I made three double batches no problem.  I moved and change my water source and my first batch was fine.  Water quality test strips look good.

  My mash bill is 11# of milled corn, 2# milled, malted rye and 2# milled, malted high diastatic power barley; total of 15# grain, 5 gallons water.  I add 2 teaspoon gypsum and adjust pH to 5.2 to 5.7 before adding corn.  I add two tablespoons of Alpha Amylase at 148-150 degrees and steep for an hour.  I add two teaspoons Gluco Amylase at 90-100 degrees and steep for another hour.  I throw in the malted grains at 90-95 degrees and steep overnight. 

  I use 10 grams of FermPro927 (brand new and kept in refrigerator) and 2.5 Tablespoons of Fermax Nutrient at 85-90 degrees and maintain that temperature range with warming matts through the fermentation.  Initial pH is 5.2 to 5.7 and I keep the pH above 4.0 by hanging oystershells and adding about eight Tablespoons of calcium carbonate over the first three days. I have never been able to get it above 4.4, but FermPro tells me anything 3.6 to 6.0 should be fine.

  The first double batch doth stalled out at about1.010, the second at 1.016 and 1.020.  I couldn’t taste much sweetness and an extra shot of yeast and nutrient didn’t wake it up.  Yields have been about 75% of the first double batch with this same water/yeast combination.  The first (good) batch came off at 1.001; it was down from the day before and still bubbling, I only took it off because I had to travel the next day.

  What to try next???

Are your temperatures getting too hot?

 

Since you are using FermPro I bet Pat Heist at Ferm solutions could give you some advice.

[NYB Distilling]

FermPro recommends fermenting temperature between 85 and 95 for FP927, so I don't think I'm too warm.