Alkalinity in dark beers

[DD2000GT]

My last three brews have developed a stong harshness at the finish and I have been beating my head up over what has changed all of the sudden. I live in the Dallas area and we have experienced severe drought this past year(s) - I can only assume the water profile has changed. Anyway, I took a PH reading today of my mash water (tap) and it was purple - hmmmm. My PH has always usually been around 6.0 so I stopped checking. Not knowing exactly that PH "purple" was as it is off the scale on the reader chart, I added 1 tsp of Phosphoric acid to the mash water (18 quarts), then took another reading - still darker than 6.0 - so I added another tsp. The reading then dropped to below 5.0 - whoops.

Ok - so I know I overdid it with the phosphoric acid - but what results should I realistically expect for a Porter being mashed with slightly lower than 5.0 PH?

Not worried - just curious.

 

[mabrungard]

Sure appears that the alkalinity of your current brewing water is too high for your grist's acidity. Considering that a dark grist typically produces higher acidity than a lighter colored grist, I would assume you would have an even harder time with the lighter beers. The saving grace might be that there are fewer dark malts in those grists to contribute the harshness you've recognized. But, you would probably see a significant improvement in your beer taste with less alkalinity in the beers.

A good option would be to send the current tap water off to a testing lab. A second best option would be to pick up an aquarium alkalinity test kit and check the water now. If the supply varies, having a good alkalinity test kit is a very good idea.

If you test the alkalinity at home and find a difference from your prior testing or water report, you should be able to plug all the original numbers into the Water Report Input sheet in Bru'n Water (Hopefully the original water report values produce a balanced water report). Then plug in the new alkalinity and figure out what the bicarbonate content probably is. Insert that revised bicarbonate 'guess' (its a guess since those home kits have limited accuracy) into the Water Report Input sheet and see if the report balances anymore. I suggest that you should be able to assume that the calcium value needs to be adjusted to help the water report balance. Move the calcium concentration up or down until the cations and anions balance. That could be used as your current water report for figuring out the dilution or acid additions to help your water meet your mashing needs.

With regard to the Porter, the beer flavor might come out a little sharper and tarter than desirable, but its very possible that the overall flavors might be pleasing. You'll want to hone your acid additions in the future to avoid overdosing. Bru'n Water gives you the tools needed to help with your mineral and acid additions.

 

[DD2000GT]

Good info - looks like I will be looking for an aquarium ph testing kit. Thanks for the Bru'n Water link - that would have been handy this morning when I was "experiementing" with the phosphoric acid. My last city water report was in 2009 - looks like I also need to hit up the gal from the water dept. again to get a recent report.

Just finished racking the Porter and the overall PH of the finished wort was about 4.8. Plan on scraping two vanilla beans in a shot of vodka and adding the extract to the fermentor - may hide some of my mistake LOL.

Every mistake makes me a better brewer.

 

[bmud0314]

I haven't played with water chemistry yet, but from everything that I have read says, for the most part, water pH BEFORE mashing is not that important. It is the pH of the mash that matters. From what I understand you are referring to just your tap water pH. The pH probably changed after you doughed in and you may or may not have had an adequate mash pH.

Though I could be misinterpreting your post

 

[mabrungard]

I haven't played with water chemistry yet, but from everything that I have read says, for the most part, water pH BEFORE mashing is not that important. It is the pH of the mash that matters. From what I understand you are referring to just your tap water pH. The pH probably changed after you doughed in and you may or may not have had an adequate mash pH.

Though I could be misinterpreting your post

Good point, I just assumed it was a mash pH. If those were adjusted tap water pH's then the effect on the mash pH would be muted. The mash is a buffered system, so its not going to drop like the tap water would. If it was the tap water pH before mashing, then all the OP did was drop the alkalinity of the tap water to nearly zero (definition: zero alkalinity occurs when the water is acidified to a pH of 4.3).

Regarding that finished wort pH, was that a post-boil pH? 4.8 is not crazy low under that condition. If its the pre-boil pH, then its a little lower than desirable. I'd live with it for now.

 

[DD2000GT]

The ph was checked pre-mash from tap water. At mash it was 5.0, after boil 4.8.

As I was getting my brew day together, that is when I first checked the tap ph thinking this may be a reason for my recent harsh brews.

 

[DD2000GT]

FYI - just got a copy of my local water report from the city (on a Sunday no less - THAT is service) - looks like Bicarbonates dropped from 112 to 88, Calcium from 52 to 47, Magnesium from 6.51 to 4.17, Total Alkalinity from 91.9 to 88. pH shows as 7.50 - so at least I know my starting point to work from.