[tomsawyer]

I have an inexpensive Hanna pH meter, and I check my calibration every time I use it.  I rarely have to re-calibrate though, it has been quite steady (within 0.1pH units, the thing reads to 0.01).  I do rinse it well after each reading and store it with storage buffer.  I have more trouble with the pH buffers, the 4.0 likes to grow a white mold.

The one other aspect of the EZ Water that I noticed, is that it doesn't take boil loss into account when calculating flavor ion concentrations.  This can increase the actual concentrations by 20-30%.  Is this the case or am I missing something there?

On the subject of hard vs soft water, I would think the bicarb is going to have some amount of buffering ability even though its not exactly in its sweet spot as a buffer since the pH is about 1 unit below the pKa.

[tygo]

The one other aspect of the EZ Water that I noticed, is that it doesn't take boil loss into account when calculating flavor ion concentrations.  This can increase the actual concentrations by 20-30%.  Is this the case or am I missing something there?

I added a tab to my spreadsheet that calculates the concentrations based on the post-boil batch volume.

[Kaiser]

I know that the EZ water calculator's pH estimate is mostly based on my work on this subject. The problem of predicting mash pH seems more complicated than I was hoping for it to be. As I keep looking into this problem and keep running experiments I oftentimes encounter contradicting results.

But I keep meaning to check the results against my own brewing logs. The problem is that I don't necessarily calculate beer color for my recipes. I know what grains make what color and that's what I tend to use. In addition to that I often re-brew recipes which limits the coverage and testing I can get for SRM-pH correlation.

In my experience, colorpHast strips do read about 0.3 units low. We did an experiment on the NB board a while back that confirmed this for the strips used by a few brewers. Check out this writre-up: http://braukaiser.com/wiki/index.php/An_Evaluation_of_the_suitability_of_colorpHast_strips_for_pH_measurements_in_home_brewing and don't it being work in progress. I meant to add more but never got to it.

Martin, I don't think that the buffer capacity if the water. i.e. the alkalinity, has much effect on the buffer capacity of the mash. At mash pH hardly any bicarbonate is left and therefore the carbonic buffer system is weak. I once titrated mashes made with R/O and my fairly alkaline well water (230 ppm CaCO3) and both mashes showed similar buffer capacity.

I wouldn't mind receiving data sets (mash water composition, grist information, mash thickness, pH) from brewers to see if there is a substantial systematic error or if there is more unpredictability than I expected.

Lennie, I don't think that there is a need to calculate the flavor concentrations post boil unless we have post boil data on which flavor concentrations are desirable.

Kai

[Kaiser]

One more note.

The pH of the base malt has a very strong influence on the mash pH and I found only a very loose correlation between basemalt color and the resulting distilled water mash pH. Because of this the calculator may work for some and not for other brewers.

Kai

[Pawtucket Patriot]

Kai, I really do appreciate the work you've done on water/mash chemistry. I've learned a lot on the subject over the past month from reading your posts and your wiki page.  But I think you're right that EZ Calc 2.0 works better for some than it does for others.

As for colorpHast strips reading low, I guess I have no way of determining that for myself at this point. I don't know that I want to invest in a pH meter right now. And, as I said above, I haven't noticed any off-flavors in my beer that I would attribute to a higher than desirable pH (honestly, I don't really have off-flavors in my beer at all -- at least that I can taste).

I think I will continue to adjust my mash pH based on the RA and SRM relationship for now, as that seems to work well for me.  What ain't broke, and that.  

[tomsawyer]

Lennie, I don't think that there is a need to calculate the flavor concentrations post boil unless we have post boil data on which flavor concentrations are desirable.

Kai

I am assuming the flavor recommendations are for post-boil.  How would they know how much boil-off you are going to have otherwise?  That does vary depending on length and vigor of boil, 20-30% reduction in volume.

[Kaiser]

I am assuming the flavor recommendations are for post-boil.  How would they know how much boil-off you are going to have otherwise?  That does vary depending on length and vigor of boil, 20-30% reduction in volume.

Lennie,

It all depends how they arrived at these recommendations for flavor ions. If it was through a series of beers brewed with different waters, the numbers would be pre-boil. If it is through beer or post boil wort analysis the numbers would have little to do with the numbers we shoot for in the water since malt also contributes these ions.

I assume that these numbers are for the water. I don’t think that the boil off difference between 10 and 20%, example, makes much of a difference when it comes to the flavor contributions from water ions.

Kai

[tomsawyer]

A 90min boil from 6.5gal to 5gal would give you a 30% increase, thats pretty substantial.  I understand that the recommendations are probably based off of base water analyses from the origin of the various styles.  I just think it would be worth switching to final boil levels going forward, its more accurate that way.  Then when we say "my beer has 300ppm SO4" we will know its that and not something between 330 and 390.  With these forums we've got the ability to quickly accumulate data to give us new guidelines.

[mabrungard]

I don't see a strong reason to concern ourselves with ion concentration from boiling.  This is getting into minutiae that would be difficult to discern in the finished beer.  

While its been pointed out that a 60 to 90 minute boil can generally increase the ion concentrations by about 20 to 30 percent, that may not be the right way to look at it.  Since most brewers boil between 60 and 90 minutes, we need to be looking at the difference between these results instead.  Under that assumption, then the difference in the finishing ionic concentrations is 8 percent or less.  That is a much less significant variation.  

Given that most of us can estimate what ion concentrations we are starting with in brewing water and can use that information to discern if they would prefer to increase or decrease a particular ion's contribution based on their taste preference, it seems pointless to say that we need to estimate what that ion's concentration might have been in the post-boil.  In addition, the action of fermentation and trub may be altering that post-boil estimate even further.  

I think we are in good enough shape to base our brewing ion adjustments on only their pre-boil concentrations.  

Kai, I agree regarding the effect of the carbonate alkalinity.  That's why I mentioned that it was for WATER.  I then mentioned phosphates which are the predominate buffer in the mash.  The phosphate buffer system is the next knowledge hurdle to cross for me.   

[maxieboy]

 This is getting into minutiae that would be difficult to discern in the finished beer.    

Getting into minutiae is in the Terms and Conditions for the use of this board!!!  

[malzig]

A 90min boil from 6.5gal to 5gal would give you a 30% increase, thats pretty substantial.  I understand that the recommendations are probably based off of base water analyses from the origin of the various styles.  I just think it would be worth switching to final boil levels going forward, its more accurate that way.  Then when we say "my beer has 300ppm SO4" we will know its that and not something between 330 and 390.  With these forums we've got the ability to quickly accumulate data to give us new guidelines.

Many ions will change more significantly during the mash and boil due to chemical interactions than they will due to concentration.  So, unless you are willing to analyze the final beer, concentrations in the final beer would be an estimate, at best.

[Kaiser]

I have to say that my measured results don't really square with the estimated pH for most recipes.

Matt,

I finally got around to putting together a spreadsheet to compare the measured mash and first wort pH and the mash pH predicted from the color (SRM) of the beer for my last 20+ batches and I'm surprised how well it actually works. The surprise is because I re-brew beers so many times that in most cases I go with my gut feel or past experiences when determining what residual alkalinity and acid addition to target.

The results are shown in this table:



green means less or equal to 0.1 pH difference, yellow is <= 0.2 difference and red is > 0.2 difference.

The predictions are in the columns labeled "mash pH (SRM and mash thickness)" and "mash pH (ARM and grist buffer)"

The red ones are two batches of Alt where the mash pH was surprisingly high and the addition of lactic acid dropped the pH much more than expected. I don't know what was going on there and consider this a fluke for now.

Then there is a Dunkel where most the pH and color is determined by the base malt. This is a difficult case to handle for any mash pH predictor unless it knows the pH of the base malt. That pH only shows a loose correlation with the color of the malt.

But it does seem to do reasonably well for beers that use a light base and specialty malts for color, at least with the limited set that I tried.

"mash pH (SRM and mash thickness)" is similar to what is published on my website, implemented in my current water calculator and most likely used by the EZ water calculator. "mash pH (ARM and grist buffer)" is similar but contains a few tweaks I'm planning to release in an upcoming version.

Kai

[Pawtucket Patriot]

Very interesting results, Kai.  Thanks for posting!

The biggest question on my mind right now regarding estimating mash pH is whether we're just getting too technical about it.  In other words, what might seem to make a significant difference on paper doesn't really make a significant difference in actual practice.  In Martin's Bru'n Water thread, I just posted about my results using his new spreadsheet in yesterday's brew session (my results using Bru'n Water were excellent, btw).  Depending on whether my colorpHast strips read slightly low, I likely hit my target pH (5.3-5.4).  But I've been hitting that range just fine with this beer -- which I've brewed several times -- using mash additions formulated solely through trial and error (i.e., adding CaCO3 until I hit my desired pH).  Using trial-and-error-based additions, my measured pH is almost always 5.2-5.3, which seems to be more in line with the SRM:RA estimates.  But at the end of the day, we're talking about a +/- .1 pH difference between my traditional method and using Bru'n Water.  I'm not criticizing Bru'n Water at all, I'm just asking whether in the end the various methodologies for calculating mash pH are just different sides to the same coin.  After all, your table above demonstrates that the SRM:RA calculated pH doesn't stray much, if at all, from your measured results.

[Kaiser]

The biggest question on my mind right now regarding estimating mash pH is whether we're just getting too technical about it.  In other words, what might seem to make a significant difference on paper doesn't really make a significant difference in actual practice.

This is a very important point and I have found myself on both sides of the argument. Over time I have learned that most brewers are a pragmatic bunch and unless something makes a huge difference they won't adapt to a new tool or technique. In addition to that most of them also don't want to be bothered with the details. This is why the EZ water calculator has been so successful and why my water spreadsheet has a basic and an advanced page. But unless you know how a tool works it is difficult to determine how much you can rely on it.

Being off by 0.1 pH units (or even 0.2 in some cases) doesn't make much of a difference. I had side by side experiments that differed in mash pH by 0.15 (I believe) and couldn't taste a difference.

In your case, the likely error of the colorpHast strips is thrown in. I don't advocate for you to buy a pH meter since those strips work just fine when you know how to read them, but if you suspect your pH to be off, change it in future batches and see how well you like the results.

The biggest value of all this is that it drives brewing knowledge forward. If we were to settle on what we have now and don't explore new ground we will get stuck and may never run across the next thing that will make brewing easier and the beer better.

Kai