Alkalinity refers to water’s ability to resist pH changes, which influences nearly every aspect of beer and is essential for a successful brew.

The role of Alkalinity in brewing

Alkalinity enables water to neutralize or resist acidity changes, meaning higher Alkalinity results in higher pH, making it less acidic. Since your mash needs slight acidity, most brewers work to lower Alkalinity.

Your brewing water won’t be the only factor in this pH, your grain will also have a major effect. Because the grain won’t be the exact same every time you brew, even if you purchase it from the same source, it will have a different impact on mash pH.

For paler beers a lower pH is essential, meaning lower Alkalinity is more important. In contrast, darker beers may require a slight increase in Alkalinity.

Alkalinity levels in your brewing water

The target Mash pH is always 5.2–5.4.

It might seem confusing to aim for the same Mash pH while adjusting your starting water’s Alkalinity and pH based on beer style. The reason for this is because the grains used in lighter and darker beers affect pH differently.

When it comes to Alkalinity levels, lower is better. This doesn’t mean that you want zero Alkalinity, just low levels. The minimum that is recommended is typically 30 – 40 ppm. The upper level of Alkalinity is typically 120-125 ppm with many trying to stay between 50 ppm and 100 ppm.

What is Residual Alkalinity?

Residual Alkalinity is the Alkalinity that is not neutralized by the water’s hardness. This brewing-specific measurement estimates pH conditions during mashing. This is because Alkalinity is reduced by the water’s hardness at higher temperatures. The equation for this is:

Residual Alkalinity = Alkalinity – ((Calcium/3.5) + (Magnesium/7))

Calcium is twice as effective as Magnesium at reducing Alkalinity in your mash, though both make a difference.

Residual Alkalinity means that, in addition to Total Alkalinity, water hardness should also be considered, as it will lower your final pH.

How to Measure your Alkalinity

There are two ways to measure Total Alkalinity, the Craft Pro Test Strips and the Craft Pro In-Lab Test Kit.

DIY Test Strips

The Craft Pro DIY Test Strips will give you an easy, affordable way to measure Total Alkalinity with each batch. These will measure Total Alkalinity along with Hardness, Calcium, Magnesium, and several other key factors for your brew.

The test strips will give you results in a range, meaning you will know if your Total Alkalinity is 0-40 ppm, 40-80 ppm, etc.

Craft Pro In-Lab

The In-Lab Craft Pro Test Kit will allow you to send a water sample to our EPA-Certified lab and get exact concentrations for your brewing water or any brewing liquid.
You will know exactly what your Total Alkalinity is, as well as exact concentrations for other parameters and several brewing specific calculations such as Residual Alkalinity.

How to lower Alkalinity for brewing

Boiling

Some brewers recommend boiling your water to lower Alkalinity. This is because boiling can remove Bicarbonate which is the primary factor of Alkalinity in drinking water. The theory behind how this works is that the Bicarbonate will bond with Calcium, forming Calcium Carbonate with is insoluble. Once the water cools, you can filter out these solids.

If you use this method, make sure to test your water after it’s cooled to ensure that the process worked. It is dependent on several factors like Calcium concentrations, so it is not as dependable as other methods.

Boiling it is easy and free, the largest problem is that it’s hard to replicate the same results over and over if you are wanting a consistent brew.

Using Acids

Adding food-grade acids reduces the Alkalinity and the pH of your water. Different acids can impart different flavors to the beer that can be complimentary if used in the correct amounts.

How to raise Alkalinity for brewing

If you are brewing a darker beer and want to increase Alkalinity, the easiest way is to use Sodium Bicarbonate, which is commonly called Baking Soda.
This is the same baking soda you will find in any grocery store and does not need to be specifically designed for brewing beer.

Conclusion:

Alkalinity is a major factor in creating great beer. But it does need to be balanced with Hardness based on what style of beer you wish to make. Darker beers need high Residual Alkalinity while paler beers need low Residual Alkalinity.