Inconsistent Acid Malt

I recently had a discussion with a pro-brewer that reported inconsistent acidity of his acid malt supply. That was the third report of inconsistent acid malt from brewers and this brewer was using the same malt from a very reputable maltster.

This result is similar to a report from a brewing supply salesman that reported that he had seen acid malt strength vary by a factor of 2. I don't know if that refers to strength between differing maltsters or differing batches, but the evidence suggests that all acid malt users should be aware of their source and its batch. Switching maltsters or batches could throw your mash pH results off.

While using a program like Bru'n Water helps get your mash pH in the proper range, its still worthwhile to monitor your room-temperature wort pH at the end of the mash to assess performance and make minor adjustments. The latest version of Bru'n Water includes an Acid Malt strength adjustment feature.

Enjoy!

Is a pH above 5.4 ok?

A recent post on a homebrewing forum asked if comments by Alechemist's head brewer, John Kimmich, were wise to follow. John recommends that mashing pH always fall within a range of 5.1 to 5.3 at mash temperature, which is roughly equivalent to 5.3 to 5.5 at room temperature.

There is little doubt that he is correct for the beer that he brews. However, we need to recognize this for Alechemist: "We are currently focused on brewing one beer perfectly – Heady Topper". That is from their website.

I agree that you shouldn't allow room-temperature mash and wort pH to rise above 5.4 for pale beers. The flavors can quickly become muddy and less pleasant. In the case of Heady Topper, I can believe that targeting 5.3 (5.5 at room temperature) may be necessary for that lupulin bomb (yummy!). But that point of view for mash and kettle pH does not hold true for our entire spectrum of beer styles.

I and thousands of other brewers have found that some beers demand a slightly higher pH target in order to smooth and refine some flavors. Most pointedly, most porter and stouts are better when their room temperature mash and kettle pH is in the 5.4 to 5.6 range. I've even assisted a large regional brewery that was having flavor problems with their porter. After implementing treatment that boosted their mash pH, that beer was recently ranked as one of the top 25 porters in the country. It had been on its way to a thin and acrid death.

So, pH does matter and its incorrect to state that 5.1 to 5.3 is THE range for brewing. Its also important to note the temperature at which you are referencing pH. The proper breadth of the range is more like 5.1 to 5.6 at room temperature and there are subsets of that range that generally favor certain beer brewing. To blindly follow John's advice is akin to saying: "One size fits all". I'm hoping that this illustrates why we need to be a little more open and knowledgeable with respect to mashing and kettle pH.

Enjoy!

Reserving Your Roast

One method intended to improve the flavor of darker beers is to delay the introduction of roasted grains (reserve them) until the last moments of the mashing period. The finely ground roast grains are added in the final minutes of the mashing rest. In the right situations, that technique can produce significant improvements in the finished beer. However, it’s not always desirable or suitable. This article illustrates the Dos and Don’ts of reserving your roast during mashing.

Roasted grains contribute color and flavor to beer. In addition, they are typically more acidic than base malts. It is that acidity that some brewers fail to understand when considering the roast reserving technique.

Mash pH is important for creating good conditions for mash enzyme action. While there are several enzymes at work in the mash and all have differing optimum pH conditions, creating a mash with a room-temperature pH of between 5.3 and 5.5 tends to provide a good compromise for all. Including or reserving roast grain from your mash should consider what the effect of that roast grain addition will be on the mash pH.

When brewing with low alkalinity water such as RO or distilled water, including roast grains in the main mash can drive the mash pH well below 5.3. Therefore, it may be useful to reserve the roast grains from the main mash to keep the mash pH in the more desirable 5.3 to 5.5 range. That enables the enzymes to do their work converting the base malt starches and sugars. Conversely, when brewing with high alkalinity water, the mash pH is very likely to be well above 5.5 when the mash is primarily base malt. An excessively high mash pH can extract harsh tasting tannins and silicates from the base malts which decreases beer quality. Including the roast grain in a mash made with high alkalinity water helps drive the mash pH lower which is hopefully closer to the optimum range.

While reserving the roast grain can help create more ideal pH conditions during the main mash when brewing with low alkalinity water, the final wort pH in the kettle is likely to end up lower than the 5.3 to 5.5 range. That can produce a more acidic or tart tasting beer. That can be fine in an Irish Dry Stout, but it may not be ideal in other styles.

Most dark beer styles with significant roast content (most porters and stouts) are more pleasant tasting and smoother when their kettle wort pH is a bit higher than typical pale worts. Targeting a kettle wort pH in the 5.4 to 5.6 range helps smooth the roast flavors and can also enhance their extraction from the roast grain. To boost pH, the mashing water needs to have some alkalinity. Tailoring the mashing water alkalinity to produce that slightly elevated kettle wort pH is desirable.

As mentioned, there are beers for which reserving roast from the main mash can be desirable. Dry stout is one that benefits from the acidic kettle wort pH, but there are several others. Those styles are typically those which color is wanted in the wort, but roast flavors are not. Styles such as Schwartzbier, Munich Dunkel, Bocks, and lighter beers that need a bit more color without roast flavor, are candidates. Typically, the amount of roast grain added is low and increased color is the goal, so the roast addition is small and less likely to drive the kettle wort pH too low.

Reserving your roast is a good technique for brewers that have low alkalinity brewing water. However, it shouldn’t be used blindly. Understanding the effects and results should help you create better beers.

Enjoy!

Boil-Off Calculation: Does It Matter?

A recent discussion on the AHA Forum brought up a useful thought about boil-off rate calculations for brewing. Several brewing recipe calculators provide the ability to calculate your kettle boil-off rate as either a percentage of the starting volume or as a rate such as gallons per hour. Since a percentage calculation is more difficult to use, I’ve typically used the gallon (or liters) per hour calculation since you can quickly correlate that loss into what your final post-boil wort volume should be.

The problem is that we still need to look at what the total water boil-off is with respect to the starting volume in order to assess how much we are concentrating the wort and the minerals in the water. For my typical 6 to 6.5 gallon starting volume, I end up boiling off about 17 to 23 percent of the water since I boil at about 1 gal/hr. Now, if I were to reduce my batch size to 2 gallons and start the boil with 3 gallons of wort, my percentage of water loss jumps to 33 percent. This happened even though I still boiled off at 1 gal/hr. As you can see, I’m going to end up with much higher gravity and I’m going to have more concentrated mineral content in that boiled wort than if I had made my normal 5 gallon batch.

So, my advice to brewers is to consider both calculations when brewing. Yes, you can use the more convenient gallons or liters per hour boil-off rate, but do check what the total percentage of water loss you are actually creating with that boil. If your water loss is more than about 20 to 25 percent, you may need to add post-boil water to dilute the boiled wort to a desired concentration or you may need to reduce the total mineral additions to avoid over-concentrating them. If your percentage loss is much lower than that, you may need to boost your mineral additions to produce your intended effect in the beer.

Enjoy!

TDS Meter: Do You Need One?

A Total Dissolved Solids (TDS) meter can be a useful tool in brewing. This meter provides an indirect reading on the ionic content of water which can give you an idea of how the water quality has varied. TDS is the sum of all the various ions (solids) in the water.

For brewers using water supplies that vary, a TDS meter reading can provide an indication of how much the water quality has varied from previous measurements. While the reading can’t tell you which ion concentrations have changed, it does give you a general indication if the water is more or less mineralized than what you normally expect. With enough meter usage and lab testing of the water, a brewer can correlate how their water quality varies with respect to a TDS reading and can better estimate what their starting water quality is and use that information to adjust the starting water profile in Bru’n Water and obtain better treated water predictions.

For brewers using Reverse Osmosis (RO) water, a TDS meter is an important tool for assessing that the system is actually producing high quality (low TDS) water. Over time, the membrane that strips most of the ionic content out of the water can fail. As that occurs, the TDS content of the treated water typically rises over time. By monitoring TDS in the treated water, the brewer can tell when the RO system is failing and will need membrane replacement. This need is particularly critical for homebrewers that purchase RO water from vending machines. Without a TDS meter, it is very difficult to determine if the treated water actually has the low TDS that the brewer expects.

An important factor to be aware of when using a TDS meter is that the temperature of the solution has a large effect on the TDS reading. The higher the solution temperature, the higher the TDS reading will be. It is best to standardize on bringing your water sample to a consistent temperature before taking a reading.

While it would be great to accurately measure what the TDS content of water is, a TDS meter reading is only an approximation. However in brewing, we don’t need to worry about exact values. We are more interested in relative readings (is today’s reading much higher or lower than readings I typically measure?). Small reading differences (<20 ppm) are not a concern. Differences of 50 ppm or more are when it is apparent that the water quality has changed significantly.

A TDS meter is a very simple device and is typically durable and long-lived. Essentially, the device is a pair of electrodes that measure the conductivity of a solution by applying voltage to each electrode and measuring the current produced through the solution. That current reading is converted into a corresponding TDS value. The figure below provides a simplified schematic of a typical TDS circuit and helps illustrate why the meters are inexpensive and durable. While you can find these meters for less than $10, purchasing a name brand such as HM Digital, Oakton, Hanna, Hach, etc is probably a better investment and those meters can be had for $20 to $30.

For brewers using RO water or those dealing with varying water supplies, a TDS meter can be a very useful tool.

Carbonate and Bicarbonate

A variety of mineral addition calculators such as those by Promash, Beersmith, or Brewater report the concentration of carbonate added with the addition of minerals like chalk. This article will help you understand why we don’t use carbonate concentration in brewing chemistry and why we do use bicarbonate concentration.

Carbonate (CO3) and bicarbonate (HCO3) are virtually the same thing excepting for an important factor...their electrical charge. Carbonate has a -2 charge while bicarbonate has a -1 charge due to the extra hydrogen proton it contains. When we deal with brewing water chemistry, we are actually working with ‘equivalents’ which is equal to the weight of the molecule divided by its electrical charge. The molecular weight of carbonate is 60 grams and bicarbonate is 61 grams. Dividing by their electrical charge results in 30 grams per equivalent for carbonate and 61 grams per equivalent for bicarbonate. So you can see that there is almost a 2 to 1 difference in their equivalents. Big difference!

Another important factor in dealing with these ions is that the pH of the solution they are in has a profound effect on whether they exist as carbonate or bicarbonate ions. The figure below shows how the proportion of these ions varies with solution pH. Since wort and beer more commonly have pH under 6, you can see that there is NO carbonate content in that pH range. In fact, the pH would have to be above 8.3 to have 1 percent carbonate. Therefore in brewing chemistry, there is no chance for carbonate to exist in our water or wort. Any carbonate picks up an extra hydrogen proton and converts itself into bicarbonate. So, bicarbonate is the ion we should be quantifying when working with brewing chemistry.

This is the reason that Bru’n Water converts all alkalinity producing mineral additions into their corresponding bicarbonate concentrations for use in the program. For example, 1 gram of chalk in 1 gallon of water produces 158 ppm of carbonate. Bru’n Water reports that this same addition produces 322 ppm of bicarbonate and does not report carbonate concentration since it doesn’t exist at our brewing pH. Similar conversion is made when pickling lime (Ca(OH)2) is used in the program.

So it is important to convert these alkaline additions into their equivalent bicarbonate concentrations. Bru'n Water does this automatically. The other calculators mentioned above don't understand this chemistry fact.

pH Meter Operation

I was recently asked what my recommendations for pH meter operation were. I’ve compiled my recommendations below. Enjoy!

Calibrate your meter prior to each brewing session to assure that its reporting correctly. Turn the meter on for several minutes to warm up and stabilize the electronics and probe before calibration and use. After that warm up, perform the calibration.

Any meter that has a 4/10 pH adjustment setting, should start the calibration with the 7 pH solution. Tweak the 7 adjustment setting to read the proper value when immersed in the 7 pH solution. Be aware that the 'proper' value changes based on the ambient temperature of the calibration solution. It might be 7.00 or some slightly different pH depending on the calibration solution temperature.

Always rinse the probe with RO or distilled water and then blow off or dab-off all the water droplets from the probe and bulb before moving from one solution (or wort) to another. Always pour out a cap full of calibration solution from the bottle before testing and don't insert the probe into the bottle of calibration solution since that can contaminate the solution. Discard each cap full of solution after you've finished the entire calibration.

Once the 7 setting has been confirmed, move to the 4 pH solution and tweak that setting to read the 'proper' value based on temperature. Rinse the probe and double check the calibration with the 7 solution. Tweak that 7 setting, if necessary. If you had to tweak the 7, you should recheck the 4 reading also.

I recommend using shot glasses made out of glass for holding wort samples. I keep the shot glasses in the freezer since the extra heat capacity of the chilled glass helps cool the hot wort more quickly. Another option is to use a thin glass container and put the container in a cold water bath to cool the sample. Since standard pH probes typically have small diameter, they fit in a shot glass easily and you don't have to place much wort in the glass. Less wort means there is less to cool and the wort cools quicker. Add only enough wort to provide enough wort depth to cover the bulb. pH meters with larger diameter probes will have to use a larger glass container.

Since a shot glass does not require a large wort volume to submerge the bulb, I use an infant medicine dropper to grab a wort sample from the tun. I let that hot wort cool for a moment by swirling it in the chilled glass to help get its temperature down before putting the probe in the wort. Getting the wort down to under 80F helps avoid stressing the probe's glass bulb. Exposing the bulb to hot and cold extremes does increase the chance that it will crack. Poof, goes the probe!

I find that it takes a few minutes for the wort’s pH reading to stabilize. If the hundreth value is jumping back and forth on the meter, the reading is essentially stabilized. If it’s still rising or falling consistently, wait a moment more. Do try and chill the wort to around 65F and record the pH then since that is generally accepted measurement standard. Record your pH reading and return the wort to the tun. Rinse the glass container and probe with RO or distilled water and dry both. Replace the glass in the freezer to rechill. I use 2 glasses so that I can assure the glasses are chilled and can check pH more frequently during the mash.

Storing the pH probe is an important issue. It either needs to be bathed in storage solution or it needs to be sealed in cap or cover with a couple drops of distilled or RO water to keep the glass bulb moist. If you are storing in a cap or cover and using the distilled or RO water, you don't want to add more than a drop or two since you don't want that water to touch the bulb since that can leach some of the electrolyte out of the probe. Electrolyte loss can eventually destroy a probe.

Boiled Water Profiles in Bru’n Water

I had a user ask why 'boiled' profiles are included along with some historic brewing city profiles. Boiling was the first form of water treatment that substantially altered water for brewing. It is simple and can be conducted by anyone. It removes calcium and bicarbonate from the water in the form of chalk, which drops to the bottom of the kettle after boiling ends.

However, not all waters respond effectively to that treatment. The ones that do can really use that form of treatment since they often have a lot of alkalinity. Alkalinity is the killer of beer.

So, the effect of boiling treatment on the water profile has been applied to those historic profiles so you can see what this basic level of water treatment might have been for those brewers. As apparent in those boiled profiles, not all of the calcium or bicarbonate is removed. The solubility of those ions prevent further reduction of their concentrations.

With the reduced calcium and bicarbonate levels in the boiled brewing water, those old brewers would likely still have needed to create some other form of acidification to make great beer. That acidification may have come from using an acid rest, adding more acidic grains such as crystal or roast malts, adding calcium salts such as gypsum, or using an external acid such as soured wort (saurgut). Therefore if starting with very low alkalinity water, it is not always desirable to add bicarbonate to match that elevated bicarbonate level and then have to acidify the mashing and sparging water to produce a desirable mash and wort pH.

My advice is to take any of those historic profiles with a grain of salt...literally. Consider targeting the levels of sodium, sulfate, and chloride in those profiles and let your calcium, magnesium, and bicarbonate levels fall where they will as you target a desirable mash pH.

Enjoy!

Does Using Acid Malt Make Sense?

I recently called using Acid Malt "stupid" on a brewing forum and then wondered if it really was. So I put an analytical spin on it to find out. Read on!

The first concern with acid malt is that its acid quantity can vary from batch to batch and manufacturer. So you may not be able to rely on its strength. Its a problem, but you can calibrate your usage with experience.

The next question was the economics. Acid malt is more expensive than typical base malt, but it does provide some extract. With that in mind, it appears that acid malt costs about $0.30 per pound more than high quality base malt. Using Bru'n Water to guide an acid malt addition, it appears that about 8 oz of acid malt were needed in a pale mash with 4 gallons of water. So that means that it cost $0.15 more to treat the mash with acid malt.

I then compared how much 88% lactic acid would be needed to equally acidify that same pale mash. Using prices from my local homebrew shop, it turned out that it cost $0.105 to provide that acid amount. So acid malt use costs almost 50 percent more to use than lactic acid.

But one of the benefits that acid malt users claim is that acid malt produces a fuller and more complex flavor than using lactic acid. A major reason why it is more complex is that other acids are part of the impurities in acid malt. One of the major acids in the impurity is acetic acid. So I revisited what it would cost to acidify that pale mash with both lactic and acetic acids. Distilled 5% vinegar is widely available and inexpensive. Acidifying to the same mash pH with those acids indicated that the cost drops to $0.074 for the mash. The resulting acetate ion concentration is still well under the acetate ion taste threshold (~175 ppm) and that means that the acetic acid use would only add some sort of nuance to the flavor...something similar to the complexity of acid malt.

So "stupid" may not necessarily be the proper term to describe acid malt use in brewing. But inaccurate and slightly more expensive are proper terms for acid malt use. You can still use what you prefer since the difference amounts to pennies in the typical homebrew batch size.

Enjoy!

Add Depth to Your Sours

After reading the analytical tests from several German Berliner Weisse beers, it was apparent that acetic acid plays a role in 'enhancing' the flavor in good sour beers. In the case of those Berliner Weisse's, they had between 0.1 and 0.6 grams of acetic acid per liter of beer with most samples being above 0.3 g/L.

Since souring with acetobactor or even brettanomyces can be problematic and difficult to control, dosing a beer with known quantities of purified acetic acid makes sense. A readily available form is distilled vinegar. It is typically sold with 5% strength.

After a few calculations, that 0.3 to 0.6 g/L acetic acid value was converted into usable volumes of 5% distilled vinegar. Dosing the vinegar at 6 to 12 mL per liter of beer will produce the desired 0.3 to 0.6 g/L acetic acid in the beer.

Wanting to avoid steering Bru'n Water users wrong, I tested the 0.3 g/L acetic acid concentration by adding 6 mL of distilled vinegar to a liter of my alkaline tap water. I couldn't taste the acetic flavor at all. Then I repeated the experiment using RO water to see if low alkalinity would help the acid flavor come through. I was JUST able to detect the flavor at that low-end dosage. So it does appear that this low end concentration is an appropriate starting point for your experiments.

So, if you find that your next sour beer is lacking complexity, try dosing the beer with distilled vinegar. For you US users, that 6 to 12 mL/L rate translates to 23 to 45 mL distilled vinegar per gallon of beer. Try it in your glass before committing your whole batch to it, but it could make a real difference!