Water Chemistry Question

[KRB]

Hi, this is my first post, and thanks for reading. I am new to water chemistry, as will be apparent I assume. I am using the supporter version on Bru'n Water to both learn and prep for modifying my water.

My water is from a city source that can have dramatic swings depending on time of year and sources being leveraged. I have spoken at length with one of the city water engineers to make sure I am reading the water report correctly, and am using the best values possible, however, when I put the information into the program, I am getting an ion imbalance of .44 (meq/L), while the spreadsheet says at .5 difference we should be questioning the the report. I have double checked the units to make sure I am not using ppb.

SO on to the first questions, is there any point in trying to get a closer balance of ions? Can this much of an imbalance throw the pH prediction off by .5 to .6 points?

To see what is happening in the real world, I made a "mini mash" equal to 10% of the planned mash. At 10 minute intervals I took pH readings and after the 20 minute mark, my mash stabilized at a pH of 5.3. I am using an Aspera PH20 (which I now realize has an accuracy of +/- .1 so I may have to upgrade at some point). The program predicts a mash pH of 5.89

I am hoping to get some suggestions on were to look to understand the discrepancy, since I am clearly doing something wrong here. If anyone wants to see the water report or the sheets, I am happy to post them.

Thanks for any input / advice!

 

[cire]

The values in your report may be averages, so accordingly not necessarily of any individual water and be the cause of ionic imbalance.

It will be difficult to make comment on your measured pH without knowing the liquor profile and grainbill.

Was the pH meter calibrated before taking readings and was the measurement taken at room temperature?

 

[BrewnWKopperKat]

... city source that can have dramatic swings depending on time of year and sources ...

FWIW, People is this situation (new to water adjustments, unpredictable water source) often start with RO or distilled water to have a consistent starting point.

 

[Silver_Is_Money]

You can't work with analytical averages across differing water sources (unless it is you who is blending them, and you know the analyticals for both sources).

As to whether or not you are "clearly" doing something wrong, whatever you do, do not look at this from the defeatist perspective that software must be right and you therefore must be wrong. Software is always highly questionable. It is assuredly not infallible. Put more faith in yourself. Such software as mash pH assistant software (from any source, mine assuredly included) is "always" working on questionable logic and quite arguably disputable math modeling, and lest we forget, ditto for softwares internal presumptions which feed the math modeling. I'm attempting to point this out with a current "stress test" of sorts that I'm running, whereby I'm asking users to report results for their software of choice for certain stressful input criteria. Many software packages are so far failing to have any of their faithful and dedicated users step forward to report. Perhaps they also fear that they are doing something wrong because of some misguided perspective that their chosen software must be infallible.

 

[CascadesBrewer]

To see what is happening in the real world, I made a "mini mash" equal to 10% of the planned mash. At 10 minute intervals I took pH readings and after the 20 minute mark, my mash stabilized at a pH of 5.3. I am using an Aspera PH20 (which I now realize has an accuracy of +/- .1 so I may have to upgrade at some point). The program predicts a mash pH of 5.89

What was the grain bill? Just a simple one with only base grain and light malts, or one with dark/roasted grains? Were there any salt additions (like Gypsum or Calcium Chloride)? Did you make any pH adjustments (acid or bicarbonate additions)? Was the grain to water ratio the same as you expect/entered into the software?

I am mostly familiar with the results of my tap water doing full volume mash BIAB, but a predicted mash pH around 5.9 would like up with what I see with a typical IPA grain bill. Maybe a little higher or lower depending on how much Calcium I add. I would need to add a good amount of acid to bring that down to 5.3, but a stout grain bill might drop into that range.

The Aspera has a reputation as a "decent entry level" meter. I suspect the accuracy is better than +/- 0.1. Did you calibrate the meter? You can do a sanity check on the meter to see how close it reads in some calibration solution.

 

[KRB]

What was the grain bill? Just a simple one with only base grain and light malts, or one with dark/roasted grains? Were there any salt additions (like Gypsum or Calcium Chloride)? Did you make any pH adjustments (acid or bicarbonate additions)? Was the grain to water ratio the same as you expect/entered into the software?

The grain bill is as follows:
.85 lb of Pale 2 row
.175 lb of German Pilsner
1.025 lb White Wheat

I used 3 quarts of water that is upstream of my filter, and I did not treat it with anything. My water to grain ratio was 1.5 qt/lb and I was careful to get this correct by weight and not volume.

The water profile I came up with is as follows: This is based on my city's water report, but it a blend of 2 different sources, based on my conversation with the city engineer.

I am mostly familiar with the results of my tap water doing full volume mash BIAB, but a predicted mash pH around 5.9 would like up with what I see with a typical IPA grain bill. Maybe a little higher or lower depending on how much Calcium I add. I would need to add a good amount of acid to bring that down to 5.3, but a stout grain bill might drop into that range.

The Aspera has a reputation as a "decent entry level" meter. I suspect the accuracy is better than +/- 0.1. Did you calibrate the meter? You can do a sanity check on the meter to see how close it reads in some calibration solution.

I calibrated the meter before use, and am confident that I did it correctly. I did not let the sample cool to room temperature, but have since done some reading that indicates that I should have.

My confusion lies in that the predicted pH is 5.89, but my readings were at 5.3. So, either the water profile is incorrect, or my readings are.

Thanks for the help!

 

[KRB]

The values in your report may be averages, so accordingly not necessarily of any individual water and be the cause of ionic imbalance.

It will be difficult to make comment on your measured pH without knowing the liquor profile and grainbill.

Was the pH meter calibrated before taking readings and was the measurement taken at room temperature?

The meter was calibrated before but measurements were not at room temp. I have read that they should have been, but that the difference might be between 2 and 3.5 off. That alone wouldn't account for the .59 difference I am experiencing. See my other response for the grain bill and water assumptions.

 

[KRB]

You can't work with analytical averages across differing water sources (unless it is you who is blending them, and you know the analyticals for both sources).

I understand that it won't ever be perfect, especially since the hydraulics of the system (according to the city engineer) prevent me from fully knowing what the water profile is at any given time. This is the reason I have not ordered a lab report on the water. The real question is whether any program will be able to help me get close enough, provided I am using it correctly.

As to whether or not you are "clearly" doing something wrong, whatever you do, do not look at this from the defeatist perspective that software must be right and you therefore must be wrong.

I don't mean to come across as defeatist, I am simply aware that there is SO much to learn about water chemistry, and I have only just begun, but that is part of the fun of brewing, always learning something.

 

[CascadesBrewer]

My confusion lies in that the predicted pH is 5.89, but my readings were at 5.3. So, either the water profile is incorrect, or my readings are.

hmmm...your water profile seems like pretty common tap water that should be decent for brewing. I feel like the 5.9 prediction is pretty reasonable for your water and grain bill. It could be that the water out of your tap is WAY off from the report you are using, but I would be more suspect of your pH reading. Maybe others could give you some steps to help verify your pH meter's readings.

You could brew a batch of beer without adjustments, and see what you measure on brew day. I would lean towards using the Bru'n Water values and making some acid additions to bring the pH down a little. I am fairly new to water chemistry myself, but it did take me several brew-measure-evaluate cycles before I was more comfortable with pH adjustments and salt additions.

 

[cire]

I would be very surprised if that grain bill mashed with any domestic supply water not treated for brewing would result in pH 5.3. I would check the buffers used for calibration.

 

[Silver_Is_Money]

I'm seeing it at about 5.95 pH. The water analyticals don't cation/anion balance though, so who knows what the actual alkalinity and bicarbonate readings for it actually are.

 

[Silver_Is_Money]

White Wheat malt and German Pilsner malt are typically more basic than for a presumption of a "standard" barley base malt, and this implies mashing at a "predicted" higher pH for this recipe than can be forecast via software that only offers a single and standardized "base malt" as an option.

 

[Birrofilo]

Until you use tap water you will be shooting a moving target if your tap water is seasonally unstable, which for what I understand means they have river or lake water in it, which is less stable than spring water.

A would use some bottled water, they for what I understand typically come from a spring water, and the values on the label should probably be more reliable of what you actually put in your mash.

 

[Smiling Frog]

While the various spreadsheet programs can do a pretty good job of predicting mash pH, there are so many factors that they never will be exact. Even batch-to-batch variations in the malt from the same maltster will affect the results, let alone different malts from different maltsters. These spreadsheets can be very helpful, particularly if you are adding salts either to build up from RO/distilled water.

IMHO, KRB, you are on the right track, but have just run into a few "gotchas". One, as you have found out, is that ATC (automatic temperature correction) on you pH meter does not mean what it seems it should mean. This is a tough one to learn and it seems you learned it early. Good going.

Another is the reported water analysis by the water company not only may not be accurate, but is likely to change not only with the seasons, but perhaps even on a whim. This is particularly true in heavily populated areas (glancing at user location) such as Southern California. This doesn't mean such water analysis reports are worthless, but it does affect how much you can trust them.

Another gotcha is that just because a spreadsheet requests the grain bill doesn't mean that it is accurately accounting for its effects. Most of these programs attempt to make corrections for color and type (e.g., base malt, high-kilned malt, crystal malt, or roasted malt). Of course, it is much more complicated than that, so these corrections will work better for some grists than others.

My approach, which I have had fairly good success with, is to use the same spreadsheet (I use Bru'n-Water), because they all work differently. I record my water source (sometimes I use tap water, other times I use RO water; it depends), my salt additions, the grain bill, the mash water volume, the predicted pH, my actual pH (at 20 minutes), and my mash efficiency. If I use acidified malt to reduce pH, I record how much. I prefer to use acidified malt instead of phosphoric or lactic acid simply because I find it easier to use and store. Of course, if you're pH reading is not to your liking, there isn't much you can do other than make adjustments for your next batch.

With this approach, I have found that the mash pH makes a profound effect on the efficiency. I also find that I am pretty good at hitting my target pH (5.25-5.49) just about every time. Does this make better beer? I don't know, but it does make me feel, at least, that I am being more consistent.

If I were you and wanted to repeat the exercise, I would add about 0.5 ounce of acid malt to the grist. My guess is that you would hit a pH much closer to 5.4. If you look at the amount of acid malt used as a percentage of your grain bill, you can scale to larger batches easily. You probably want to limit the amount of acid malt used to 3% of the grain bill to prevent it from affecting the flavor.

 

[Brooothru]

If I were you and wanted to repeat the exercise, I would add about 0.5 ounce of acid malt to the grist. My guess is that you would hit a pH much closer to 5.4. If you look at the amount of acid malt used as a percentage of your grain bill, you can scale to larger batches easily. You probably want to limit the amount of acid malt used to 3% of the grain bill to prevent it from affecting the flavor.

Agree with everything except the amount of acidulated. Think you might have meant 0.5 pounds instead of oz.

 

[Silver_Is_Money]

Using 5.95 pH and 2.05 Lbs. of grist and the Weyermann 1% drops mash pH 0.1 points rule of thumb for acidulated:

5.95 - 5.40 = 0.55 pH points of pH drop needed
2.05 x 0.01 = .0205 Lbs of Acid Malt per 0.1 points of downward pH shift
0.55/.1 = 5.5
0.0205 x 5.5 = 0.11275 Lbs. of Acid Malt
0.11275 Lbs. x 16 Oz./Lb. = 1.804 Oz. of Acid Malt required (or 51.1 grams)

 

[Brooothru]

Your math is indeed correct, sir!

My error was in not completely and carefully reading the thread where the OP listed his grist at ~2#, then compounded the error (7x) by conflating his grist bill with my average grist bill of 14# to which I would nominally add 0.25-0.50# acidulated malt to achieve similar pH values.

I hope I did a more thorough job of calculations on this year's taxes.

 

[Smiling Frog]

Using 5.95 pH and 2.05 Lbs. of grist and the Weyermann 1% drops mash pH 0.1 points rule of thumb for acidulated:

5.95 - 5.40 = 0.55 pH points of pH drop needed
2.05 x 0.01 = .0205 Lbs of Acid Malt per 0.1 points of downward pH shift
0.55/.1 = 5.5
0.0205 x 5.5 = 0.11275 Lbs. of Acid Malt
0.11275 Lbs. x 16 Oz./Lb. = 1.804 Oz. of Acid Malt required (or 51.1 grams)

I suspect that "Rule of thumb" is based on barley malt grists. The grist in question is more than 50% wheat malt, which I suspect affects both the mash pH as well as the ideal "target pH" for best conversion. In any case, using more than 3% acid malt to a mash blindly is ill-advised as it can show up as unwanted flavors. My recommendation of "about half an ounce" is based on 2% of 2.05 Lbs being 0.65 ounce, or "about half an ounce". Depending on how that affects both the mash pH and efficiency, it could be increased, but I'd be wary of going over 1 ounce.

 

[Silver_Is_Money]

Per a Weyerman publication titled "pH In The Brewery" (with emphasis theirs)

Importantly, Acidulated Malt NEVER imparts “sour,” acidic notes to the finished beer, as long as its portion of the grain remains below 10%!

In the same publication they detail the progress of a mash which recieves 5.5% by weight Acidulated Malt.