First Lager with Built Water from Distilled - Low Efficiency

Brewed my first lager this past weekend with "pilsen" water build from distilled, my effeciency went from 75% to 60%.

I used 9.75 lbs of moravian pilsner malt and .5 lb of carapils. The mash water was 3.20 gallons of distilled water treated with:

.4 g of CaCl
.4 g of MgSO4
.4 g NaHCO3

I mashed at 151 for 60 min. I sparged with just distilled water and and added the remaining minerals (per proper ratio of sparge water) into the boil.

I did not have a pH meter to verify the mash pH. But shouldn't the chemistry of the water with the pale malt bring the ph down to the mid to low 5s?

The only other thing I narrowed down my effeciency loss to was draining the mash tun too quickly, i usually open the valve pretty slow.

mklojay said:

I did not have a pH meter to verify the mash pH. But shouldn't the chemistry of the water with the pale malt bring the ph down to the mid to low 5s?

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No. You need to add acid for that traditionally in the form of sauermalz or sauergut. This is especially important with Pils as the water is soft (no pH lowering calcium) and the little bit of Carapils isn't that effective. See the Primer.

Unfortunately you did the opposite of what you should have done i.e. you added alkali in the form of bicarbonate. You added 400 mg icorresponding 400/61 = 6.6 mEq. Pilsner malt has buffering capacity of 25 - 45 mEq/kg-pH and you used 4.4 kg so that the buffering of the ash (from that alone) is 110 - 200 mEq/pH so your pH shift from the bicarbonate would be 0.03 - 0.06 which isn't too bad but it is in the wrong direction.

I see that the OP was trying to duplicate the published Pilsen water profile with the assumption that distilled water has zero alkalinity. He didn't really need to bump up the bicarbonate content, but the result wasn't a huge problem. Probably only a tenth higher than desired for the mash pH.

The big problem I see with the mash is that the mash thickness is quite high at 1.25 qts/lb. It looks like the mash water volume could and should be taken to 4 gallons to thin the mash to a reasonable value. 4.5 gallons would not be out of the question either. That extra thick mash may be a reason that the efficiency was less than expected.

mabrungard said:

I see that the OP was trying to duplicate the published Pilsen water profile with the assumption that distilled water has zero alkalinity. He didn't really need to bump up the bicarbonate content, but the result wasn't a huge problem. Probably only a tenth higher than desired for the mash pH.

The big problem I see with the mash is that the mash thickness is quite high at 1.25 qts/lb. It looks like the mash water volume could and should be taken to 4 gallons to thin the mash to a reasonable value. 4.5 gallons would not be out of the question either. That extra thick mash may be a reason that the efficiency was less than expected.

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Ok so the mash pH shouldn't have been that far off, on the assumption of the zero alkalinity of the distilled water?

I always mash my ales a 1.25 qt/lb and get better effeciency. Are more sugars extracted with pilsner malt using a 1.75 qt/lb ration?

The mash pH probably is a problem. You want 5.3-5.5 and probably have 5.7 or higher. Don't really see that the mash thickness would be a problem but I suppose it might. Fixing the mash pH and being certain that the mill is set properly will probably be the big swingers.