Article

Charging Up Alkalinity, All-in with Allspice, and Enzyme Dynamics

Q
I am starting to try and understand the pH and minerals that Affect my beer. I have well water and therefore I have a softener to treat the water. This puts my levels of calcium and magnesium at zero because they are negated by the sodium. I also have no chlorides or sulfates because it is well water. My total alkalinity is 160 ppm. my question is, if I understand and I did the math correctly my total alkalinity and residual alkalinity are the same?

Megan Bodi
via email

A
Oh boy, this topic is one of the more confusing ones in all of brewing and I will do my best to keep this answer clear. Toward this goal, I am using a brief Q&A flow to tackle each part of your question, plus several questions of my own, in discrete bits. Not the most elegant form of writing, but hopefully clear! Much of the intermediate information about residual alkalinity falls into the “so what?” category of information, but is required to get to the end result. So buckle your seat belt, grab a cup of coffee (or beer), break out a calculator, and get ready for a deep dive into water calculations.

Q: Does a water softener remove calcium and magnesium from water?

A: Yes, water softeners remove calcium and magnesium. Salt-based softeners, the most common type used at home, add two sodium ions (Na+) for each calcium ion (Ca+2) removed from the water being treated, and add two sodium ions (Na+) for each magnesium ion (Mg+2) removed from the water being treated. If you have to add bags of salt (sodium chloride) to your softener, you have a salt-based softener. Some people prefer using potassium chloride in these softeners and the principal is the same, except two potassium ions (K+) are added instead of two sodium ions (Na+).

Q: What about the chloride that is part of the salt added to the softener; is this also added to the water being treated?

A: No, chloride is not added to the water being treated because the chloride does not bind to the resin beads inside of the softener during the resin regeneration cycles. These cycles are required for softeners to properly function because they replace calcium and magnesium ions that are bound to the resin with sodium or potassium ions. The chloride component of the salt is flushed away with the calcium and magnesium ions that are displaced by sodium/potassium during the regeneration cycle.

Q: Does well water contain chlorides and/or sulfates?

A: It depends on the water source. Some groundwater sources are rich in these ions and others are not. So-called gypseous waters percolate through gypsum, aka calcium sulfate, and contain significant amounts of sulfates, and many natural water sources contain significant levels of chlorides. Testing is required to know the specifics of any water source. General knowledge about the local topography is very helpful in knowing the basics about your water. Geological maps are a good resource when it comes to researching particular regional differences in ground water.

Q: What is residual alkalinity?

A: Dr. Paul Kolbach developed the concept of residual alkalinity (RA) in 1951 to help compare waters from different brewing regions of the world. Kolbach’s metric compares carbonates, the components in water that increase the pH of mash and wort, to calcium and magnesium, the components in water that decrease the pH of mash and wort.

Q: What units are used to express RA?

A: RA is either expressed in terms of CaCO3 equivalents or in ˚dH (degrees German hardness) equivalents. Since Kolbach was German, his RA method uses ˚dH. Water hardness in the US, Britain, and France is based on CaCO3, explaining why RA is also expressed in CaCO3 equivalents. These differences in communicating water hardness are one reason that this topic is confusing and difficult to clearly explain. Here are the various standards:

• 1˚ US hardness = 1 ppm CaCO3
• 1˚ British Hardness = 1 grain/gallon CaCO3 = 14.3 ppm CaCO3
• 1˚ French Hardness = 10 ppm CaCO3
• 1˚ German Hardness = 10 ppm CaO

Q: What is meant by equivalent?

A: This is perhaps the single-most confusing part of discussing water hardness. Different compounds have different molecular weights, but many chemical reactions are a function of charge and are not influenced by weight. An equivalent weight expresses the concentration of something in terms of another thing. In the case of water hardness, the concentrations of calcium, magnesium, and carbonate are all expressed using a single unit of measurement; either equivalents of calcium carbonate or equivalents of calcium oxide. When concentration in mg/L (the same as ppm) is converted into an equivalent concentration, the term used is milliequivalent or mEq.

To express 1 ppm calcium, for example, in terms of CaCO3, the following equation is used:

Ca+2 as CaCO3 = ppm Ca+2 x equivalent weight of calcium carbonate ÷ equivalent weight of calcium

Ca+2 as CaCO3 = 1 ppm Ca+2 x 50 ÷ 20 = 2.5 mEq

To express 1 ppm calcium, for example, in terms of CaO, the following equation is used:

Ca+2 as CaO = ppm Ca+2 x equivalent weight of calcium oxide ÷ equivalent weight of calcium

Ca+2 as CaO = 1 ppm Ca+2 x 28 ÷ 20 = 1.4 mEq

Chart 1 below shows the ions of interest to this topic as milliquivalents of CaCO3 and CaO. This information is not immediately useful, but the RA calculation uses equivalent weights and it can be frustrating using a conversion without understanding what it means and why it is required.

Chart 1

Q: How is RA calculated using US degrees of hardness?

A: Residual alkalinity as ppm CaCO3 = Total alkalinity mEq – [(Ca+2mEq ÷ 3.5) + (Mg+2mEq ÷ 7)]. The reason that the concentrations of calcium and magnesium are divided by 3.5 and 7, respectively, is to account for the solubility of calcium phosphate and magnesium phosphate, and to equate the acidifying power of calcium and magnesium to the alkalizing power of carbonate/bicarbonate (usually expressed as HCO3 in a water analysis).

This equation can be simplified by substituting the conversion from ppm to mEq. RA as CaCO3 = (ppm HCO3– x 0.82) – [(0.71 x ppm Ca+2) + (0.59 x ppm Mg+2))] If your water analysis has the value “total alkalinity as CaCO3”, use that value instead of “ppm HCO3 x 0.82” in this calculation.

Here is an example where HCO3 is 360 ppm, Ca+2 is 76 ppm, and Mg+2 is 18 ppm. RA as CaCO3 = (360 x 0.82) – [(0.71 x 76) + (0.59 x 18)] = 231 ppm as CaCO3.

Q: How is RA expressed as CaCO3 converted to ˚dh?

A: Hardness as CaCO3 x 0.056 = ˚dH. Brewers living in a country reporting alkalinity in terms of CaCO3 may want to use this conversion when reading literature with reference using German degrees.

Q: How is RA applied to brewing?

A: RA is used to predict how mash pH is influenced by brewing water. Chart 2 can be used as a guideline.

Chart 2

RA < 5˚dH or 85 ppm as CaCO3 is recommended for pale colored and hop forward beers. Darker beer can handle higher RA because darker malts are acidic and balance the alkalinity found in water.

Q: My total alkalinity is 160 ppm with a pH of 6.5. If I did the math correctly, my total alkalinity and residual alkalinity are the same?

A: You are correct; your water is softened and contains no appreciable level of calcium and magnesium (in the absence of testing, this is a reasonable assumption), so RA = total alkalinity. All brewing water benefits from calcium because calcium stabilizes alpha amylase, improves trub formation, and helps to precipitate oxalates from malt. A general rule is to have at least 50 ppm of calcium in brewing water. This means your water needs some calcium. Magnesium influences mash and wort pH, and can add a metallic-like bitterness to beer when used at high levels. Without adding some sort of acid, your water is not well-suited for most beer styles because of the high RA. The RA equation can be used to calculate the calcium concentration required to reduce the RA of your water to 2, for example.

2 RA (as CaCO3) = (160 ppm total alkalinity) – [(0.71 x ppm Ca+2) + (0.59 x 0)], and solving this equation results in Ca+2 = 226 ppm.

Chart 3 compares water from three famous brewing centers. It is interesting to note the type of beer traditionally brewed in these cities and the RA of the three waters.

Chart 3

Q
I tried a beer in which allspice pepper had been used and I want to experience this spice in my beer. What style do you recommend for your use? Should I use the allspice berries whole or grind them before use, and at what point in the process should I add it; boil or fermentation?

Lalo Severo
Montevideo, Uruguay

A
One of the easiest ways to work a spice into beer recipes is to consider how the spice is used in cooking and then create a beer that mimics the food concept. More advanced uses of spices include using spices to substitute and/or complement hops, add depth and complexity to fruit, augment yeast characters, and to round out complex beers that may seem a bit disjointed. Whatever the purpose, it is important to maintain balance when brewing with spices because it is very easy to overdo any one spice addition.

Allspice, also known as myrtle pepper and Jamaican pimento, is a berry harvested from the Piementa dioica tree that is native to the Caribbean, Mexico, and Central America. So named because it seems like a blend of cinnamon, nutmeg, and clove, allspice is used in a variety of dishes including Jamaican jerk chicken, aromatic breads and baked goods, pickles, desserts, and savory stews. Allspice lends itself to beer styles that play well with aromatic phenols, such as pumpkin ale, rich dark beers like porter, dunkel lager, imperial stout, and maibock. I am thinking beers with some residual malt character that can support the intensity of allspice. Judicious additions of allspice may also work well as accents to saison, hefeweizen, and beers with other aromatics such as vanilla, basil, rosemary, and chocolate. And any discussion of spices and styles these days is incomplete without mentioning pastry stout, the catch-all style for just about any and all ingredients.

Spices, like hops, can be used ground or whole, and can be added in the boil, during fermentation, or after fermentation. One of the challenges to using spices is usage rate. Whereas hops are labeled with alpha acid content and brewers can calculate how much to add based on this value, spices come with no similar indicator. This means that spice additions are approximate, even when using a recipe. For these reasons, I prefer to add spices to beer after fermentation is complete.

If you like precision and knowing what is going to happen in advance, begin by making an allspice tincture using vodka and freshly ground berries. A day of contact time is about all that is required for most spice tinctures, especially when ground spices are used. Tinctures allow for blending trials using small samples of beer to determine the preferred dosing rate. I like to take about 100 mL of beer and pipette small volumes of whatever it is I am trialing into the beer while swirling and smelling with each addition to determine approximately how much ingredient is required for the desired intensity. I then set up 3-5 glasses with 100 mL of beer per glass and add my test ingredient at a range that brackets the concentration in the first trial. This method is a great way to take the guesswork out of spicing.

Some brewers and cooks feel this food science approach to brewing and cooking lacks romance and prefer more rustic methods. If you want control without the pipette and graduated cylinder, consider containing your allspice berries in a spice bag and adding the bag to a keg or fermenter before filling with beer. Periodically sample your beer and rack it to another keg or bottle when the intensity is to your liking. I have used this approach to add oak flavor to beer when I was not sure how much oak was needed to produce the right amount of oakiness.
Spices can always be added to the kettle, but this method allows for the least amount of control unless you have previously gone through a recipe development process. Adding spices to the kettle is easier than adding during or after fermentation, and also adds a heat sterilization step that offers a level of surety to the process.

Q
“These two enzymes, though they work in concert, behave differently in response to changes in mash thickness and mash temperature. This is because of the difference in their stability at high temperatures. Alpha-amylase has an optimal range from 149 to 158 °F (65 to 70 °C). The optimal range for beta-amylase is 126 to 144 °F (52 to 62 °C).”

I perform Brew-in-A-Bag, and am researching mash thickness, then I came across this information in BYO which got me thinking about the temperatures of mashing. If we need the alpha-amylase for the primary process of breaking down the starch molecule chain, then beta-amylase to clip off maltose. Reading the optimum temperatures for these enzymes, then why wouldn’t mash temperature profiles have a stand at “149 to 158 °F (65 to 70 °C),” then back the temperature off to “126 to 144 °F (52 to 62 °C)” to optimize conversion?

Michael Armstrong
Newcastle, Australia

A
The old alpha and beta amylase temperature conundrum! It does indeed seem that the temperature optima for these two enzymes is reversed for the purpose of mashing. Beta amylase produces maltose by “biting” off maltose molecules from the non-reducing end of starch molecules. In the case of amylose, there is one reducing end and one non-reducing end, and in the case of amylopectin, a heavily branched molecule, there is one reducing end and multiple non-reducing ends. Amylopectin is often compared to a tree, where the trunk represents the reducing end and the tips of the branches represent the non-reducing ends. Alpha amylase randomly breaks bonds within amylose and amylopectin molecules, and in the process produces one reducing and one non-reducing end with each broken bond. The result of this activity is more sites for beta amylase to act upon, and this is the reason that brewers often lament that beta amylase activity occurs before amylase activity in a step mash.

As you suggest, this seems like an easy enough problem to solve; start in the alpha amylase range and simply cool the mash down to where beta amylase is most active. But this does not really work, and herein lies the conundrum. Enzymes are proteins with catalytic activity and are pretty resilient molecules. Change the solution pH over a pretty wide range and the surface charge of proteins change, and in the specific case of enzymes this charge change affects enzyme activity. Similarly, changing temperature results in a change in enzymatic rate. But changes in pH and temperature beyond enzyme-specific limits, cause an irreversible movement in the three dimensional structure of the protein that completely stops enzymatic activity. This structural change is known as denaturation. Fried eggs, cheese, tofu, grilled steak, and trub are all examples of food featuring denatured proteins. What this all means is that beta amylase is denatured when the mash is held at the alpha amylase optimum for any appreciable time.

Let’s take a few steps back from this discussion and consider what happens in a normal infusion mash that is held at about 149 °F (65 °C). Although this temperature is higher than the optimal temperature for beta amylase and will eventually lead to denaturation, the denaturation is not instantaneous. As temperature increases, so does the rate of denaturation. This temperature is also not the optimal temperature for alpha amylase, but alpha is active at 149 °F (65 °C) even though its optimal temperature is 158 °F (70 °C). In other words, infusion mashing is a compromise mash. And it works quite well when brewing with well-modified malts.

There is a traditional mash type that plays with the balance of the various malt enzymes, and that is the decoction mash. The classic triple decoction begins by bringing water and malt together for an initial temperature in the 104–122 °F (40–50 °C) range where beta-glucanase and proteases are active. A portion of the thick mash (that portion that settles when the mash is not mixed) is moved to a kettle and heated to a boil. Many descriptions of decoction mashing quickly skips past this step, but this step is relevant to the topic at hand, so let’s dive in a bit deeper.

When the thick mash is pumped to the kettle, much of the mashing liquid, or thin mash is left behind. This liquid contains enzymes that will hang about until the boiling mash is returned. In the meantime, the thick mash is heated up to about 158 °F (70 °C), held for about 10–15 minutes, and then heated up to a boil. The brief rest at 158 °F (70 °C) allows alpha amylase sufficient time to make a few nice whacks into the tree-like structure of amylopectin. This thins the mash out and really helps with mash pumping, and it also results in more non-reducing ends for beta amylase to act upon.

After this first boil, the mash is pumped back and mixed with the dilute, enzyme-containing, mash that was hanging about during the boil. Depending on the specifics of the brewery, the mash temperature increases to about 140 °F (60 °C) where beta amylase is most active. This process is repeated to bring the mash up to about 158 °F (70 °C) for the conversion rest, and is repeated once more to bring the mash up to about 169 °F (76 °C) for mash-off. The decoction mash method does move the system up and down in temperature, and up and down through the temperature optima of the various malt enzymes that we brewers have at our disposal. Exactly what you are asking about. A key thing with the decoction mash is that a portion of the mash, about 2⁄3 of the total, is not boiled and thus preserves enzymes.

The purpose of this answer was not to explain how to adapt principles of decoction mashing to BIAB, rather I wanted to review how decoction mashing does more than simply heat mash using traditional brewing methods. Hopefully this information is useful for you in your pursuit of mashing perfection!

Issue: November 2018