Lactate Taste Threshold Experiment

Last weekend I did a yeast handling presentation to Brew Free Or Die club members and I took the opportunity to conduct a lactate taste threshold experiment with 8 club members. While it had little to do with the topic of the technical session it is a subject where I wanted to do some experimentation for quite some time.

Acidulated malt and 88% lactic acid are very popular acids for mash pH correction but since lactic acid has a rather distinct taste the question that is on many brewer’s minds is: “How much lactic acid is too much“.

Since in most cases lactic acid is only added to counteract water alkalinity and bring the mash pH into the desirable range of 5.3-5.5 it can be assumed that the added lactic acid will not lead to a lower than normal beer pH. In other words, we don’t have to worry about beers that taste sour.  But we do have to worry about the characteristic taste of lactate. Lactate is what’s left when lactic acid gives up its proton to neutralize a base or contribute to pH changes.

The experiment was designed such that the acidity of the lactic acid was neutralized with slaked lime. While that also adds calcium in addition to the lactate it matches brewing reality where highly alkaline waters oftentimes come with high calcium levels. I had the choice between calcium (from slaked lime) or sodium (from sodium hydroxide).  Both calcium lactate and sodium lactate tasted very similar in water which shows that sodium doesn’t necessarily lead to a salty taste. I decided to go with calcium lactate since calcium is generally the dominant cation in alkaline waters.

I was very surprised to see how many of the tasters struggled with identifying the flavor in the 4 sets of samples they were given (water, Bud Light, Budweiser and Sierra Nevada Torpedo Ale). Even levels as high 1200 mg/l, which amounts to a whopping 23% acidulated malt, were not correctly identified by some tasters.  Below is a link to a more formal write-up of the experiment and those interested can go ahead and check my numbers.

Here is a chart that shows for each taster the highest lactate level that was identified as tasting like the control:

highest lactate level that tasted like the control


After having done this experiment and having tasted samples with added lactate myself I think that a safe upper limit of 400 mg/l lactate or 7% acidulated malt is reasonable with the assumption that the mash and beer pH are at acceptable levels. While 7% is higher than the 5% that is currently seen as the safe upper limit for acidulated malt use it should be noted that there might be other benefits to  reducing the amount of minerals in a given water before acidulated malt is used to neutralize the remaining alkalinity.

A formal write-up of the experiment can be found on the wiki: Lactate Taste Threshold Experiment

A New Mash Chemistry and Brewing Water Calculator

When I started helping Brewer’s Friend as a technical adviser I couldn’t help but notice that the mash pH predicted by its brewing water calculator was way off. Since I have done extensive work on brewing water and mash chemistry already I took this as an opportunity to develop a new Mash Chemistry and Brewing Water Calculator from scratch. The goal was to build something that provides a simple and intuitive user interface yet implements the underlying chemistry to at a level of accuracy that is generally not done in brewing water calculators. In fact the only calculator that goes to that extent is A.J deLange’s NUBWS (Nearly Universal Brewing Water Spreadsheet).

Since Brewer’s Friend is an online recipe calculator the new calculator would also become an online tool. This worked very well in its favor since it is very cumbersome to model complex systems in spreadsheets. PHP, or any other programming language for that matter, makes that type of modeling much easier. In addition to that modern web browser technology makes it simple to create dynamic forms that can readily adjust the form to only asking the user for information that is actually needed based on the context.

That was 3 months ago and after many long nights of coding, re-coding, testing and even running more mash pH experiments version 1.0 has finally been released and is available on Brewer’s Friend.

When you first open the calculator it presents itself like any other basic water with sections for source water, salt additions, grist, mash pH and final water report following this flow chart:

Flow chart for basic use of the calculator

Flow chart for basic use of the calculator

But that’s not all. For those who need want to do more complex water treatment calculations, the full flow chart looks more like this:

Full flow chart for brewing water and mash chemistry calculator.

Full flow chart for brewing water and mash chemistry calculator.

All these additional section are hidden by default and can be shown on demand.



The first release features makes these features available:

  • Blending of two water sources
  • Bicarbonate/carbonate content can be set from either alkalinity or bicarbonate. pH can also be entered for increased accuracy
  • Electrical balance (ion balance) of the source water
  • Simple GH&KH measurements can be used as a crude way of specifying the source water.
  • Report of basic and advanced water parameters of the source water. Among the advanced properties are temporary/permanent hardness and CO2 partial pressure
  • supports all major salts (including magnesium chloride) as well as the hydroxides slaked lime and lye
  • Alkalinity reduction through boiling and slaked lime. These are features that rely on a more accurate implementation of the water’s carbo system
  • Wide range of supported acids including the less commonly used citric, tartaric and acetic acid.
  • Salt and acid additions can be made to all water or only the strike (mash) water
  • A different water source can be used for sparge water. In most cases that might be reverse osmosis water when the tap water is suitable for mashing.
  • Salt additions to sparge water or kettle
  • Sparge water acidification with a wide range of acids.
  • Detailed report of the treated mash water
  • Support for undissolved chalk.
  • Grist pH properties can be estimated from beer color or malt bill
  • Mash pH prediction based on balancing the various weak and strong acid systems that might be present (carbo system, weak acids and grist)
  • overall water report based on the mash and sparge water profile
  • target water comparison of the overall water report

For now this tool is only available as a stand-alone calculator but Brewer’s Friend is planning to integrate it into the recipe editor. This will eliminate duplicate entry of the beer’s malt bill. It will also allow the user to use saved source water profile(s).

Go ahead and give it a try. If you have feedback, positive or negative, please let me know:

Mash Chemistry and Brewing Water Calculator

In subsequent posts I’m planning to write more about some of the discoveries I made while writing this tool and how it’s mash pH prediction does compared to actual mash pH data that I have.


Beer color to mash pH (v2.0)

I finally completed an article than I promised when I wrote the Sep/Oct 2011 Zymurgy article on mash pH and beer color: Beer color to mash pH (v2.0). Don’t get too excited, though. This is very heavy on math and should merely be seen as a reference to how I arrived at the current SRM to mash pH formula I implemented in the most recent versions of Kaiser_water_calculator_US_units.xls and Kaiser_water_calculator.xls.

File:SRM to mash pH formula 22.gif



Brewing water spreadsheet update

I decided to give my brewing water calculator a face lift and also add some new features that brewers were looking for. The face lift happened mostly on the “basic” page, which is now more intuitively grouped into the sections for

  • base water
  • mash and grist info
  • salts and acids
  • resulting water profile and mash pH prediction

These are other things I changed or added:

  • changed the treatment of undissolved chalk such that it only contributes half its calcium since it contributes only half its alkalinity. Chalk’s solubility in mash seems to be limited and what does not dissolve and contribute to a rise in alkalinity should not contribute calcium ions either.
  • salt additions can now be made in g and mg/l. You can select the unit
  • the salts to be added can be reported in g and tsp. The latter is useful if your scale breaks down or you don’t own one yet.
  • lactic acid and phosphoric acid are supported. Are there many brewers who are actually using hydrochloric or sulfuric acid? I may add support for those later.
  • water boiling for alkalinity reduction has been added to the “advanced page”. This was easy to add since I already supported lime treatment
  • pH shift estimation for the major water treatment steps
  • salts can be added to all the water or strike water only. If they are only added to the strike water, the resulting water profile for the strike water or the overall water can be reported.

But a number of features remained the same:

  • The basic and advanced pages are still there. Anything entered in the basic page will automatically carry over into the advanced page. The idea is to support a wide variety of users.
  • the tall and narrow formatting remained in order to better support its use on mobile devices
  • I avoided macros or the use of fancy functionality in hope that this spreadsheet can be supported by mobile devices
  • the SRM based mash pH prediction is still there. Compared to some tests I’m running with grist based mash pH prediction, it does surprisingly well and is actually more accurate in most cases.
  • support for SI and US units. Under the hood it uses SI units almost exclusively. There is a spreadsheet version that is preloaded with US units even though this changes only 2 fields.

The new Kaiser_water_calculator.xls can be found in the Ingredients section on my site.

If you find bugs or have suggestions for improvements let me know here or send e-mail to “kai at braukaiser dot com”.

About pH Targets and Temperature

I noticed that the topic “At what temperature should mash pH be measured” comes up once in a while.  Just recently I had an e-mail and an on-line discussion with a fellow home brewers on the same subject.

Fact is that the pH of a solution changes with temperature. It is caused by a change of the dissociation constants of the various acids/bases that are in the solution. Even water is considered an acid since it can donate hydrogen ions, although in most cases it is not dominating pH at all. The extent of the change depends on the substance. By the same mechanism even the pH optimum of enzymes may shift with temperature it is also dependent on the ionization state of the acids in the protein. I believe that the 0.35 correction factor for mash temp (65 C) vs. room temp (25 C) pH contains both the aspect that the actual pH in the mash is lower at 65 C compared to 25 C and that the pH optimum of the amylase enzymes shifts a bit from the value that can be observed by room temperature mashing.

But none of this matters since by convention pH values in brewing are reported as the pH of a room temperature sample. This arises from the laboratory practice of cooling pH samples before pH is tested. While pH meters can correct for temperature and their probes may be able to withstand higher sample temperatures, testing only cooled sample extends the life of the probe. This common practice also means that reported pH optima and pH ranges are for room temperature samples even though the actual reaction happens at higher temperatures. A.J. deLange mentioned to me the “by convention” aspect which is an important argument in this discussion. “By convention” means that we could do it differently but we settled on this particular method in order to communicate our observations and recommendations more clearly.  Just as an example, another brewing measurement where we have a convention is the expressing the extract content in specific gravity. Rather than Plato, which measures the extract content by weight and which is something that doesn’t change with temperature, specific gravity does change with temperature and we assume that all those measurements are corrected for temperature such that they apply to a 68 F sample. The practice is and should be done for pH measurements. To be exact you’ll have to cool hot samples and warm cold (e.g. beer) samples.

It’s also helpful to take into account how we arrived at these pH optima/ranges. They are determined by conducting a series of mashes (at correct mash temp for that enzyme) with differing pH. The pH is tested in a room temp sample. The amount of product produced during these reactions (sugar, for example) is then plotted over this room temperature pH.

The same is true with boil pH recommendations where kettle boils at different pH values were done to determine how wort quality changes when the boil pH changes.

One problem is that hardly any author is explicit about this. I assume that most of them see it as a given that they talk about pH from room temperature samples. Briggs was the only one I found that made a distinction. This lack of explicitness, if this is a word, seems to cause a lot of confusion with home brewers.

As for the origin of this confusion, I believe that early home brewing literature and publications are to blame. John Palmer’s 1st edition of “How to Brew” states this:
“When you mash 100% base malt grist with distilled water, you will usually get a mash pH between 5.7-5.8. (Remember, the target is 5.1-5.5 pH.)”

In this sentence he mixes room temp and mash temp pH values. The 5.7-5.8 base malt pH is correct when seen as the pH of a room temperature mash sample while the 5.1-5.5 pH target is only correct when seen as a mash temp pH target with a conversion factor of 0.35. With the correction the room temp sample pH target range is 5.45 – 5.85, which is more correct.

The pH optima that John cites for various enzymes seem to be mash temp pH values. He doesn’t quote a source but the only source that I found which lists mash temp pH values is Briggs’s Brewing Practice and Science book. In this he also gives room temp pH numbers.

I came across this inconsistency when I started reading more technical brewing literature. The pH optima listed for the enzymes for the given optimal mash pH ranges just didn’t line up with what I heard from other brewers. It took me a while and doing my own pH vs. conversion experiments to get a clearer picture of this topic.

And to answer the question that is most interesting to brewers, I believe that the optimal mash pH range is 5.3-5.5 for light beers and 5.4-5.6 for darker beers when testing a room temperature sample of the mash. This pH range is a good compromise between optimal enzyme activity, good boil pH and good cast-out wort pH.

I think we figured out what’s the problem with chalk

Ever since I discovered that chalk, when simply added to water or mash, does not raise the pH as much as an equal amount will do when it is dissolved with CO2 (see these old bog posts: How much alkalinity does 1 ppm of CaCO3 (Chalk) really add? and Undissolved vs. dissolved chalk in the brewing water) I was wondering why.

Recently the discussion got some traction again and got more of A.J. deLange’s attention than before. He proposed that chalk dissolves only slowly at mash pH. Slow enough that the time it takes us to mash doesn’t dissolve all the chalk. In hindsight this looks like a logical explanation. It also breaks with the common (home) brewing wisdom that chalk added to water or mash will dissolve since the mash pH is low enough. And then there has been this “bug” in John Palmer’s water calculator which for a while has been seen as the only reference for mash pH calculations. His water spreadsheet assumes that chalk adds only half its alkalinity potential to the mash. While it may not have been intended it ended up being a close enough approximation of chalk’s behavior in the mash.

A few days ago I did a simple experiment. I rinsed another 500 ml of 7 Plato wort from the spent grain of a batch of IPA I was brewing. To 250 ml I added ~110 mg chalk and to the other I added ~130 mg baking soda. Based on mash titration experiments these salt additions should have been capable to raise the pH by more than 1. I was not really looking for quantitative results but for a qualitative measurement of the pH behavior when chalk or baking soda are added to wort.

After the salts were added I kept stirring and recorded the measured pH values over time. The resulting graph is shown below.

It is apparent that the pH change caused by baking soda is sudden and remains fairly constant over time while chalk causes a sudden initial rise and a further gradual rise that continues over 15-20 min. Even though the 110 mg chalk added about 1.57 mEq residual alkalinity and the 140 mg baking soda added about the same amount (1.55 mEq), baking soda caused 2x the pH change. This lines up with previous observations I made regarding undissolved chalk.

If chalk does not completely dissolve we also need to assume that it releases only part of its calcium to the mash. This has been corrected in the current version of my Kaiser_water_calculator.xls which assumes that undissolved chalk contributes only half its calcium and half its alkalinity.

New article about mash pH contol

I finally completed a new article that took almost a year to write. It took so long not only because I took a break from brewing and writing about it for a while, but most importantly I wanted to write an article that is well supported by brewing experiments and close observations of mash pH in batches of beer that I brewed over the last year. All too often get brewers caught up in the theoretical aspect of water and mash chemistry with the aim to calculate everything with the best precision possible. But what is commonly overlooked is that measurements are not precise enough to require this precision and, what is mots important, malt’s reaction to pH changes is not that predictable anyway. To capture that aspect experiments are necessary.

The objective of this article was to give the advanced brewer an insight in the major factors that affect mash pH and how it can be corrected. Based on experiments it also gives guidelines that allow the estimation of mash pH changes based on the water profile, water treatment additions or mash additions, without focusing too much on this aspect. Those are largely based on mash pH experiments I conducted including the data published in The effect of brewing water and grist composition on the pH of the mash.

With this article I also released a updated version of my water calculator. But more on this later.

Click here: Mash pH control


Calcium and Magnesium’s effect on mash pH

I have evaluated the effect of calcium and magnesium on the mash pH before when I investigated the pH effects of various waters (The effect of brewing water and grist composition on the pH of the mash). This time I repeated these experiments but didn’t add the calcium and magnesium salts before dough-in but after dough-in. I was wondering if there is a difference or if I could repeat my observations.

The experiment set-up was fairly simple. 7 glasses were filled with 160 ml distilled water and heated in a ~75C water bath. 7 40 g samples of Rahr 2-row were weighed and milled separately with a ~0.75 mm mill gap resulting in a mash thickness of 4 l/kg. Strong calcium chloride and Magnesium sulfate solutions were prepared. The mash samples were doughed-in 3 min apart from each other. Each of the mashes had an initial mash pH of 63-64 C. 5 min after dough in different amounts of either the calcium brine or the magnesium brine were added. One mash remained unchanged. 15 min after the salt addition a sample of the mash was removed, cooled and its pH was recorded. Another sample was taken 60 min after the salt addition.

The results, along with data from previous mash experiments, are plotted in the chart below:

The first observation is that the distilled water pH for the Rahr 2-row is surprisingly low for a pale malt. I also observed this when I used this malt before. The earlieexperiment used pilsner malt which had a more typical distilled water mash pH of 5.7 and 5.8 respectively. Another observation is that magnesium is less effective than calcium in lowering the mash pH. A fact that is already known from the residual alkalinity equation where magnesium hardness is seen as half as effective in neutralizing alkalinity compared to calcium hardness.

As the calcium content increases the achieved pH drop gets smaller which suggests that the curve is approaching a saturation. However, this matters little to practical brewing since the amounts of calcium needed to drop the pH that low by far exceed the recommended amounts. At 42 mEq/kg, for example, the calcium content of the water in a 4 l/kg mash is already 212 mg/l. 50-150 mg/l is the recommended range for brewing water. In case of magnesium 40 mEq/kg mean ~110 mg/l magnesium in the mash water. This is way more than the magnesium levels commonly found in brewing water. Since magnesium is not as effective as calcium anyway it would not be a good choice for lowering the mash pH anyway. If the salts are only added to the mash water, their “flavor active” concentration can be spread over the total water volume used to brew that beer which will reduce the overall impact.

To put this in perspective ~2.1 g of gypsum (calcium sulfate) needs to be added for every kg of malt in order to drop the mash pH by 0.1 units. If we assume that for the average 12 Plato beer ~7.5 l water are needed for every kg of malt, this gypsum addition is equivalent to a water calcium increase by 65 mg/l and a sulfate increase of 155 mg/l.

For calcium chloride only 1.8 g are needed. The calcium content gets bumped by 65 mg/l (when spread over all the water even though the calcium is only added to the mash) and the chloride content gets bumped by 115 mg/l.

There is little change in between the 15 min and the 60 min pH measurement.

Mash Titration

Continuing the titration experiments I got a chance to titrate some mash tonight. The titration procedure was the same as described in the previous post and I won’t repeat that here.

But here are the stats for the two mashes that were prepared. One for titration with HCl and the other for titration with NaOH:

  • 100% Maris Otter Pale Malt pulverized with small coffee grinder
  • 3 l/kg mash thicknes
  • distilled water
  • mash temp was ~61 C
  • mash time was 15 min
  • samples were both cooled to 25 C for the titration experiment
  • The results are shown here. This time I followed convention and plotted pH over the amounts of titrant that was added:

    This time the slopes leading up to the normal pH, which was 5.82, are pretty much the same. Based on A.J. deLange’s feedback the large discrepancy between these slopes in the wort titration experiment may have been the result of the fact that the normal pH for malt and wort is at the lower end of the pH where there is a fairly linear relationship between mEq/kg and pH

    I assume a repeat of the wort titration experiment is in order.

    Wort And Beer Titration

    I finally got around to conducting two
    experiments which I wanted to do for a while now: the titration of
    wort and beer.


    Titration is a process in which
    increasing amounts of a strong acid and/or base are added to a sample
    while the pH of the sample is monitored. This gives an indication of
    the pH buffer capacity of the sample at various pH points. It can
    also be plotted as a nice graph, a so called titration curve. More
    about the basics of pH and titration can be found here : An Overview
    of pH


    The set-up of the experiment was as
    simple as this: A diluted solution (~0.64%) of hydrochloric acid was
    prepared by mixing 37% Muriatic Acid with water. I don’t like working
    with the concentrated form of this acid and the amounts of acid
    needed tend to be so small that they would be difficult to measure if
    the undiluted acid is used. In addition to that, a dilute solution
    (1.25%) of sodium hydroxide (NaOH), which is a strong base, was also


    The wort, and later beer, sample was
    weighed and placed into a glass cup along with a stir bar. The pH
    meter probe was affixed to the glass cup using masking tape. (Masking
    tape seems to be a very useful tool in my brewery). While being
    stirred on a stir plate the pH was constantly measured. To determine
    the amount of acid/base that has been added a small cup was filled
    with the acid/base solution and placed onto a digital scale which
    provided a resolution of 0.01 g. The scale was zeroed while the cup,
    titration solution and a pipette was on the scale. By doing so the
    total amount of titration solution removed from the scale would be
    shown as a negative weight.


    The wort sample had an extract content
    of 12.7 Plato.


    The initial pH was measured and
    recorded. After that a small amount of acid was added and once the pH
    reading stabilized this reading and the amount of acid added so far
    was recorded as well. The process was repeated until the sample
    reached a pH of less than 2.0.


    Titration of a fresh sample using a the
    strong base (NaOH) and acid/base titration of a beer sample followed.
    The beer sample had an original gravity of 12.0 Plato and an apparent
    extract of ~3.0 Plato. The beer and wort samples were from different


    Using a spread sheet acid and base
    additions were converted to milliequivalents of acid/base per extract
    weight in the case of the wort sample and per original extract weight
    in the case of the beer sample. This was seen as a suitable approach
    since the pH characteristics of the samples are largely determined by
    the dissolved substances.


    Using this data the added amounts of
    acid (negative mEq/kg) or base (positive mEq/kg) were plotted over
    the pH of the samples which resulted in the following chart (click for larger version):

    As expected the wort sample had a
    higher initial pH (5.18) than the beer sample (4.62). But what is
    also apparent is that around that pH the beer sample has a higher
    buffer capacity than the wort sample. Buffer capacity is the amount
    of acid that is needed to change the pH by a given amount. The unit I
    like to use is mEq/(pH*kg) which is milliequivalents of acid/base for
    each pH shift of 1 unit and for each kg of substrate. The latter
    doesn’t count the water. For beer this buffer capacity was 92
    mEq/(pH*kg) when adding the base and 76 mEq/(pH*kg) when adding the
    acid. Ideally they should be the same but measurement errors could
    have lead to this difference.


    In the case of the wort sample,
    however, there was a distinct difference between the buffer capacity
    when adding an acid (29 mEq/(pH*kg)) and when adding a base (64
    mEq/(pH*kg)). I don’t know how to explain this and this is not the
    first time I noticed this discrepancy. It also appeared to me during
    my mash pH experiments. In order to double check my titration
    solutions I calculated how much of the NaoH solution I would have to
    add to a sample of the HCl solution to neutralize all the acid. I
    then performed that experiment and found that the actual amount I had
    to add was within 1.5% of the expected amount. So my titration
    solutions had their expected strength. At least in relation to each


    The beer sample also shows an area of
    strong buffer capacity around pH 6.5 (where the curve is steepest
    between the two flatter sections). It is possible that this is the
    1st pKa of carbonic acid, which is at pH=6.4, since the
    beer sample was slightly carbonated.


    While the beer and wort samples were
    not from the same batch it is very likely that fermentation creates
    additional pH buffers which are the cause of stronger buffer capacity
    of beer.




    This experiment does little when it
    comes to finding ways to make better beer, but it gives insight into
    the pH buffer characteristics of both beer and wort. One thing to
    take away is that around the normal pH for wort and beer there is a
    nearly linear relationship between the amounts of acid/base added and
    the pH shift. This means that if the addition of X amount of acid
    drops the pH by Y the addition of 2X acid will also drop the pH by
    2Y. Within the pH range that is practical in brewing there won’t be a
    case where the addition of a little bit more acid causes the pH to
    suddenly “fall off a cliff”.