Mash pH has caused a lot of confusion in the homebrewing world. So much that even some experts have made some questionable remarks on what is correct and what is not. I’m writing this because I recently had the same problem. I did a lot of research on mash pH information and got a lot of conflicting answers. It gets even more confusing when you read about how mash pH differs in the actual mash vs the cooled wort sample. It’s enough to make your head spin.
I’m actually glad I had this problem because it helped me understand the issue first hand. I was able to sort all of this out with the help of other homebrewers who have a far more in-depth understanding of this topic than I do. Hopefully this will help anyone who has the same questions as I did.
Contents
Ideal Mash pH Range
Before I jump into anything, it’s important to understand that mash pH is measured at room temperature, not the actual hot mash. The optimal mash pH of 5.2-5.6 is referring to the room temperature measurement.
This was initially incorrectly published in a BYO article and caused a slew of backlash. The ideal mash pH target range for a cooled wort sample has historically been 5.2-5.6. So when a mash pH figure is given for a specific style of beer, let’s say 5.
4, that number is referring to the cooled wort sample, and not the actual hot mash temp, which could actually be a lower number. The true difference in variance is debated, but as far as I’m concerned it only adds confusion and isn’t really needed.
Why Mash pH Matters?
Importance of Mash pH | Brew
Although perfectly good beer can be made without considering your mash pH, having an understanding of the cause and effect of correct pH on the mash will help improve your brewing.
What is pH?
pH is the measure of the acidity or alkalinity of a liquid. Neutral pH is considered as 7, which is the pH of pure water. Most tap waters will run somewhere around 7 or higher depending on how hard the water is.
pH is measured using strips or a digital pH meter. Although strips are adequate as a guide, they are hard to read so it’s well worth investing in a proper pH meter for accurate results. These are relatively expensive and also require careful handling as the probes are very delicate but they can also be used to measure fermentation pH, useful for all brewing but essential for sour beers.
pH and the Mash.
The ideal mash pH range is considered to be between 5.2 and 5.5. Mash pH is different from the pH of your water as the malts are acidic so they will lower the pH once added to the water.
Having the correct pH will:
– Improve enzyme activity during the mash. This will increase conversion of starches to fermentable sugars.
– Lower pH in the finished wort. Improving yeast health during fermentation and inhibiting bacteria growth.
- – Improved hop extraction rates in the boil and giving smoother bitterness.
- – Better protein and polyphenol precipitation both during the cold break and post fermentation.
- – Improved clarity in the finished beer with reduced chill haze.
- – Improved flavour and clarity stability as the beer ages.
- Factors effecting mash pH
- Although mash pH can be predicted it can be difficult to accurately predict so measure and then adjust on subsequent brews.
- The two main factors affecting your mash pH are water and malt.
- Water
A general rule of thumb is hard water will be more alkaline leading to increased mash pH. Softer water will be more acidic and therefore decrease the effect on mash pH.
This is not quite as straight forward as just measuring the water’s pH as it is the alkalinity of the water (usually measured in CaC03) and it’s mineral content that will dictate the effect on pH.
You can purchase test kits to measure the alkalinity but you will also need to know the calcium and magnesium content to more accurately predict the effect on the mash pH. Most water requires some treatment when brewing pale beers to ensure the mash remains around 5.2.
Grist make up
Malt is acidic. The malting and heating process causes the acidity to increase and therefore darker malts will lower the mash pH even more. If you have high alkaline water then you may well be able to brew dark beers without having to do anything to lower the pH. In fact you may need to increase the pH if you are brewing dark beers in soft water areas.
Measuring and adjusting
A digital pH meter is the best method of measuring pH. You need to cool the sample to around 20c before you measure the pH as temperature affects pH and the ideal range 5.2 – 5.5 is measured at room temperature. High temperatures will also damage the probe.
- There are several options for adjusting the pH.
Water and Mash pH
Water chemistry for brewing is a complex topic, which is why entire books have been written about water and brewing. Unfortunately, many of these books assume you have a good knowledge of chemistry, along with microbiology and brewing.
Assuming you have access to a “reasonably good” water source, you should not have to do much to your water to use it to brew beer. Most municipal water in the United States can be used right out of the tap with no adjustment. If, however, you have a well or other source with particularly hard or soft water, then you can purchase bottled water from your grocery store and use that instead.
Interestingly, extract brewers can use distilled water for their brewing because all the minerals needed for brewing are already in the malt extract. When the maltster created your malt extract he/she mashed grains and then concentrated the wort down by removing the water, which means the ideal set of ions for brewing are already in the concentrated malt.
If you are an all-grain brewer with a “good” water source, the most important thing to worry about is mash pH.
The proper mash pH has a number of positive effects on your beer—improving both the flavor and stability of the finished beer. Mash pH is simply the pH of the mixture of water and grains in the mash tun.
You can best find it by measuring it with a pH meter or pH test strips. Ideally, you want a mash pH of 5.2–5.6 when you mix the water and grains.
You might recall from high school chemistry class that pure distilled water has a pH of 7.0, but most municipal water sources have a higher (slightly alkaline) pH above 7.0, due to minerals they pick up from ground and surface sources.
Grains, in contrast, are acidic, meaning they will lower the pH of the water/grain mixture. Dark roast malts are very acidic and will have the largest effect, while pale malts are only slightly acidic.
So when we mix our slightly alkaline water with our acidic grains, we get a pH that is often in the range of 5.0–7.0. That will depend on how alkaline the water was to start with, how much acid the water itself can absorb (which is measured by the water’s residual alkalinity), and how much dark vs. light malt we use.
Since we want to get the mash pH down to 5.2–5.6, we often need to use additional acid to drive it down further. This is particularly true for light beers, which don’t have enough acidic dark malts to reach the desired range.
For a homebrewer, this means adding small amounts of lactic acid, phosphoric acid, or acidulated malt to the mash until you get the pH down to the range you need.
Lactic acid is probably the most easily found in an average homebrew store.
So to summarize: start with a good “drinkable” water source and start your mash. Use a pH meter or high-quality pH strips to measure the actual pH of your mash. Finally, if needed, add small amounts (typically only a few ounces/milliliters total) of lactic acid to bring the mash down to the 5.2–5.6 range and then continue brewing your beer.
Learn how to evaluate your water chemistry and make adjustments to brew the best beer possible with Craft Beer & Brewing Magazine®’s online course, Brewing Water: A Practical Approach. Register today!
PHOTO: MATT GRAVES
How to Adjust the pH of a Mash
If the pH of the mash is too low (too acidic) the addition of Calcium Carbonate will work well to raise it. In some cases, especially if you are making a very dark beer such as a Stout or Porter, you may have to settle for a mash pH as low as 5.0, but under no circumstance should you add more than 2 teaspoons of calcium carbonate to a five gallon mash.
If the pH of the mash is too high (too basic/alkaline) the addition of calcium in the form of Calcium Sulfate (aka Gypsum) or Calcium Chloride is the most acceptable way to lower it.
To raise or lower the pH of a Mash , additions of calcium carbonate (to raise pH) or calcium sulfate / calcium chloride (to lower pH) are recommended
- Add ½ teaspoon at a time
- Mix well
- Recheck the pH after each addition
If these are not available, or if you are brewing with very soft water, then the addition of phosphoric acid can accomplish acidification of the mash. Teaspoon additions can be added incrementally until the desired pH is achieved.
Another product available is called Mash Stabilizer. This product will automatically lower, or raise, your mash to 5.2 pH. All you do is add it to your mash tun, and it does the rest. Mash stabilizer is a very easy product to use that eliminates the need to use pH Strips or a pH meter.
Acid Rest Technique
There also is a technique called an “”acid rest”” which can be employed to lower the pH of the mash by varying degrees. The enzymes responsible for this are most active at a resting temperature of 95 °F for 15 minutes to a half an hour. So, start your mash at 95 °F for 15 – 30 minutes, then raise the temperature to the standard 152 °F for however long the recipe calls for.
If you are trying to raise the temp in our All Grain Brewing Cooler Systems, we recommend draining a gallon of wort from your mash tun, bring it up to a boil, and then add it back into your mash tun. Make sure to stir the hot wort back in so the higher temperature disperses throughout all the grains. This will usually get you very close to the 152 °F range.
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Here’s What Happens if Your Mash pH Is Too Low
Mash pH is a crucial element in the brewing process, determining the effectiveness of various mashing parameters and affecting the overall quality of beer. So, what happens if the pH value falls below the optimum?
If your mash pH is too low, it can result in a less pronounced taste and reduced body. The beer would still be good, but, generally speaking, maintaining a pH level between 5.2 and 5.8 is optimal. If the pH falls to 2, the brewing enzymes won’t be active.
In the following sections, I’ll be diving further into the effects of mash pH being too low, the optimal level of mash pH, the relevance of the indicator, and how to adjust mash pH to achieve a better-tasting result. Let’s get started!
The Effects of Mash pH Being Too Low
It is important to pay attention to the pH value while preparing mash. Typically, so long as all the previous steps of the brewing process have been handled well, it should fall within the optimal range without the need for any additional help.
However, due to various reasons, the main one usually being the water alkalinity, the mash pH can be lower than expected. While lower pH is typically not as bad as too high of a pH, it is still an issue that shouldn’t be overlooked.
How Low Is Too Low
Before we get into more detail on the subject of low mash pH’s effects on the result of beer brewing, it is essential to determine from the start what value should be considered too low.
Everything below pH 5 is lower than the optimal pH value for mash. Everything under pH 4 falls into the category of not recommended, and a pH of 2 or less indicates that the fermentation simply won’t happen.
Ideally, the mash pH should not be lower than 5.2. That is the consensus of most professionals.
Recommendations can differ slightly depending on what sort of beer is being brewed. As dark beers are known to drop to lower pH levels than light ones during the fermentation process, for them, the lowest pH point can be more stretched.
A pH range of 4.25 – 4.6 is widely recognized as appropriate for all malt beers. For adjunct beers, mash pH can be as low as 4.0, and it can go even lower than that for sour beers.
The Effects on Flavor
For many brewers, the taste of beer can be considered the primary characteristic of the finished product. While evaluating beer taste might be subjective, we have chemistry at our service to determine the basic flavor qualities and in what way they are affected by low mash pH.
The pH value will influence the taste of beer directly. The recommended mash pH is 5.2-5.6, and during the boiling and fermentation processes, it will decrease, with ales ending up in the range of 3.8-4.2 and lagers in the range of 4.2-4.75.
However, if the mash pH is lower from the beginning, it will result in the beer pH dropping beyond the desired values in subsequent brewing phases as well.
At pH lower than 4, the following effects on the beer flavor have been reported:
- Reduced body, meaning the reduced fullness of taste and ‘thickness’.
- Increased bitterness and sourness in the taste.
- Drying in the aftertaste.
- Reduced flavor stability (poorer flavor qualities over a period of time).
The Effects on Enzyme Activity
- While enzymes can be active at pH values lower than the recommended standard, the process will take significantly longer.
- At pH lower than 4, a rapid decrease in catalytic enzyme activity has been reported, meaning that the mash time can double or even triple depending on the exact value.
- It is strongly recommended against letting the mash pH drop below two since, at that value, enzymes lose most of their catalytic activity.
If enzymes experience denaturation due to the decreased pH value, their activity won’t be restored.
At that point, the process is irreversible.
As there are different enzymes involved, you may find varied information regarding the ideal mash pH level for each. However, the stated optimum of 5.2-5.6 works well for most mashes.
The Optimal Mash pH Level
In short, mash pH is formed when the malt meets water. Water is an alkaline component that pushes mash’s pH to be higher, while the malt acids tend to reduce the overall pH value.
As a result, the two main factors that influence mash pH are water and malt. Other factors also influence the process, but their effects are not fully studied yet.
Despite the complexity of determining the impact of these variables on the pH value and their precise effects on the end result, a general consensus on the optimum figures of mash pH does exist.
Most experts agree that the desired optimal level for mash pH is between 5.2 and 5.6. This number is backed by scientific data regarding the general influence of the pH value on mashing parameters.
Research Data
The Best pH for Brewing and Distilling (And How to Adjust It!)
While experienced brewers can tell when something wrong without the need for pH meters and thermometers, we mere-mortals need a little help.
That help comes in the form of pH meters. They are important tools for making sure that the balance between acidity and alkaline in the fermentation process is correct.
A pH meter is necessary regardless of what you brew, whether it is beer, wine, or distilling. To make things a little easier, digital pH meters are a popular tool that allow you to measure the pH with greater accuracy.
However, pH meters need to be calibrated properly before they are used, to obtain an accurate result.
To keep your digital meter from degrading, it must be properly stored.
How Do You Calibrate and Use a pH Meter for Brewing?
Any pH meters you buy will have already been calibrated.
However, they lose accuracy when transported as well as over time. Generally, a calibration buffer solution will be supplied with the pH meter.
The buffer solution has a specific pH which you can use to test the meter and then calibrate the pH scale. There is usually a little screw on the pH meter which you must turn to correctly set the pH level. You may need to move the scale to make it more acidic, or more alkali.
Digital pH meters have a calibration button that you press when the probe is submerged in the buffer solution. Once it has had a moment to stabilize, you press the calibration button again and the meter will self-adjust to bring its reading in line with the buffer solution pH.
There are usually two buffer solutions, a 7 pH and 4 pH to which the pH meter will set itself. In more sophisticated laboratory models, a 10 pH buffer solution may also be used.
What is pH and How Does it Affect Fermentation?
PH levels affect the shape of proteins. During fermentation, a collection of enzymes produced by the yeast is responsible for the many metabolic processes that occur.
An enzyme is a protein that performs the metabolic process. As an example, sucrase is an enzyme that breaks sucrose down into fructose and glucose. This means that they act as organic catalysts.
