Please diagnose my issue

I don't see anything wrong with the way you are treating for chlorine. (Though I don't know offhand what a "normal" chlorine level would look like compared to yours.) That aside, I wouldn't expect "dull" flavors from chlorine. I'd expect it to combine with phenols, creating plastic/band-aid flavors.

It's possible you're extracting more tannins than you did before, which would depend partially on the pH your wort is reaching during the sparge. Additional tannins could cause astringency, and/or chlorophenols if combined with chlorine, but again, not the "dull" flavor I think you're describing.

For the dull flavor, I do wonder if your final beer pH is higher than normal, and so...was the wort pH higher than you think? Definitely check your meter.

Also, can you try hard to describe the "off taste that I do not know how to describe?" Does it remind you in any way of anything? (Plastic? Band-aid? Medicinal?)

 

I would recommend checking your pH meter like @VikeMan said, but also check your final post fermentation pH.

Would this matter much if you're batch sparging or just if you're fly sparging?

 

One word: sulfate. Use more gypsum. Try that first and let us know if it doesn't work.

 

IMO 178 ppm SO4 shouldn't be the cause of his "dull" flavor problem, subjective though the term may be.

 

All other things being equal, the risk is much lower with batch sparging.

 

“The beers are tasting dull, have an off taste that I do not know how to describe, and most notably the hops are very muted.”

Boy, the aspects to “tasting dull” and “hops are very muted” sure sounds like a water issue to me. I am sure that you have considered this as well given the amount of detail you provided concerning your brewing water.

You mentioned the water profile for you latest IPA: “Ca=115, Mg=3, Na=74, Cl=118, SO4=178, HCO3=29.”

Of the ions of Ca, Mg, Na, Cl, and SO4 the only value that seems a bit ‘out of whack’ is the Mg level. In past published materials, John Palmer has a recommend range for Mg of 10-30. He also states: “Magnesium is an important yeast nutrient in small amounts (10 -20 ppm)”. Given that last statement I don’t envision a low Mg level yielding a flavor impact.

You mentioned: “I ended up measuring a mash pH=5.38.” That is a good value if you measured accurately.

Well, I am stumped at this point in time.

Hopefully some other water folks like @utahbeerdude will have some thoughts.

Cheers!

 

Just heating the water will drive off the chlorine, no need to add sodium metabisulfite (campden tablets).

My overall guess is that your city water contains less minerals, and therefore the bland flavors. Distilled water is probably not helping if that's the case.

Another note, city water readings vary, and depending on where the water is coming from and the time of the year, there can be great fluctuation.

 

Yeast get as much magnesium as they need from the wort (i.e. the malt). I usually build from distilled water, and those batches have 0 added Mg. I think you are correct in that low Mg in the water shouldn't cause an off-flavor, though too high a level can cause some interesting problems.

 

There has been some discussion of the sulfate level. FWIW, John Palmer recommends a range of 50 - 350 and the value of 178 is comfortably within that recommended range.

Also the Chloride/Sulfate ratio for the IPA water is 0.66 which should be OK for a hop forward beer; this ratio should not mute hops.

Cheers!

Edit. Maybe having a higher sulfate level will increase the perception of 'hoppiness' but I do not think it should be required?

 

There's a distinction between chlorine, which degases fairly readily, and chloramine, which (if I understand correctly) does not. Many municipalities use chloramine to treat their water. I don't think it's a bad idea to take steps to eliminate chlorine (in its various forms) from the water. Personally I prefer to let my water sit out overnight, and then to add a small amount of ascorbic acid (vitamin C) to eliminate any residual chlorine. (NYC does not add chloramine to its water, but in any case ascorbic acid removes both chlorine and chloramine.)

When I hear "muted hops" and "dull hop flavor" I think "oxidation." But nothing indicates any change in procedures that would have this result.

My only other observation is that the water seems somewhat high in sodium chloride. I would try a batch built up from distilled water, with a more normal level of sodium, and see if this addresses the problem.

 

Maybe it's a hop problem?
Are the hops old?
Did your hops travel in a moving van through the desert in the middle of summer?
Did you try newer fresher hops?

 

I keep my hops in a van down by the river.

 

I'm so curious about this. I need to know!!!

Looking at it again...

Point #2: What is your total Alkalinity? Not just the measurement of components.

And how did you calculate this: "My last beer was an IPA with the following water after treating, Ca=115, Mg=3, Na=74, Cl=118, SO4=178, HCO3=29"?

Point #3: As long as you're not over-sparging your pH should be OK. (Scary as it is, most craft breweries do not even bother with pH readings or sparge-water acidification). But your thoughts on extracting tannins confuse me... do the beers seem astringent?

 

The subtle issues are the toughest ones to figure out. You sound like a fairly advanced brewer. I assume you have a tap set up. Have you tried replacing the lines? Maybe after 70 batches they are ready to go, and it just happened to coincide with your move?