[S. cerevisiae]

I obtained an unusually low extraction rate on the last batch that I brewed.  My mixed-grist extraction rate for the batch was 28 points per pound per gallon, which is three to four points lower than my average mixed-grist extraction rate.  I did not change my strike or sparge hot liquor-to-grist ratios, so I chalked the lower efficiency up to higher mash pH and higher sparge liquor pH.  This batch was the first one that I have made since installing an acid neutralizing (calcite) filter where I have not added pH adjusting salts to the mash and lactic acid to my sparge liquor.  I added a small percentage of acid malt to the grist per Bru'n Water.  The sparge liquor was accidentally left untreated.

With that said, all I can say is that I need to see if I can repeat the results of this batch with a different yeast strain because it is one of the best tasting green beers that I have ever made with domestic malt.  The batch actually has malt flavor.  I have never been able to extract much in the way of flavor from a predominately domestic 2-row grist, regardless of extraction rate.  I have always treated domestic 2-row like tofu in that it needs dark caramel or some other strongly-flavored specialty malt to give it flavor when making an ale; otherwise, one ends up with either a bland product or hop water.   

I am beginning to wonder if a non-optimal pH can be beneficial to flavor development in some cases.  I was certain that the oversight I made with my sparge liquor would have resulted in harsher flavors whereas the exact opposite occurred with this batch.  At 119 mg/l as CaCO3, my neutralized water supply contains the highest concentration of carbonate hardness that I have ever used in brewing.  I have always had the luxury of working with a naturally relatively soft water supply.  Maybe the difference is due the fact that hardness in my water supply is mostly temporary due to being the result of the dissolution of calcite in the acid neutralizing filter?   All I know is that I do not have enough data to draw a conclusion.

[erockrph]

It would be interesting to get an analysis of the mineral content from the finished beer compared with a similar analysis from a previous batch that went through your usual adjustments.

Of course the results still beg the chicken-or-egg question - is the flavor difference strictly due to the concentration of flavor ions and pH of the finished brew, or was the change a result of alterations to the mash chemistry/efficiency/etc. It's all very interesting food for thought.

[S. cerevisiae]

The results are definitely non-intuitive. The batch is more than likely an outlier.

[morticaixavier]

what was your mash pH? I've found leaps and bounds more malt character from a mash pH of 5.5 vs 5.3         

[HoosierBrew]

what was your mash pH? I've found leaps and bounds more malt character from a mash pH of 5.5 vs 5.3         

Yep, same here.  It's why I like to mash dark beers @ 5.5 - the malty richness seems to come out more and take the edge off of the more acrid roasted malts.

[S. cerevisiae]

what was your mash pH? I've found leaps and bounds more malt character from a mash pH of 5.5 vs 5.3         

That's interesting because my mash pH was 5.78 at room temperature, and the pH of my untreated tap water usually runs around 7.2 at room temperature.  I normally attempt to keep my mash pH in the 5.50 to 5.60 range at room temperature, and shoot for a pH of around 6.0 with my sparge liquor.  The pH of my tap water was in the 5.9 to 6.0 range before I had the calcite filter installed.  Maybe this batch wasn't an outlier after all.  As Jon alluded, the malt flavor is also less edgy, which was a surprise.