The Best Water Profile for Hard Seltzer (Starting Water & Minerals)

If you’ve tried to make hard seltzer in the same way you would brew beer, you may have noticed that it didn’t turn out the way you expected. Hard seltzer is heavily reliant on the water profile used.

The best water profile for homebrewing hard seltzer is similar to, but not exactly, a Dublin-style profile. Hard seltzer requires water high in alkalinity and yeast nutrients built up from a distilled or RO water base. If you don’t have access to Dublin-style water, reverse osmosis or distilled water is your best starting point.

Whether you are already experienced in adjusting water profiles or not, keep reading to explore other options. Great homebrewed hard seltzer will soon be added to your repertoire.

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Bottling homebrew with an auto siphon

What is the ideal water profile for hard seltzers?

All beers have styles of water profiles that they work best with, and hard seltzer is no different. Particular water profiles will contribute to great tasting hard seltzer.

When homebrewing hard seltzer, the ideal water profile is similar to a Dublin style. Hard seltzers require high alkalinity to offset the pH drop that occurs during fermentation. In addition to the specific water profile, you will need to add yeast nutrients due to the lack of a nutrient source such as the wort in beer brewing.

The biggest differences between homebrewing beer and hard seltzer are the fermentables. Beer brewing uses a wort that contains many of the sugars, nutrients, and minerals that yeast needs.

Hard seltzer brewing lacks a wort to provide these nutrients. This is why the water you use is so important. An ideal water profile will provide pH buffering without containing too many minerals that could result in a cloudy or oddly tasting result.

The Dublin-style water profile is a great place to start as it is already highly alkaline. That said, you will likely need to increase the alkalinity. It is important to regularly check the pH of your batch.

Another important consideration for your water profile is the sulfate to chloride balance.

In beer, the balance of these two, or imbalance, changes the emphasis on certain flavors. In hard seltzer, it is best to have them balanced so as to not change the refreshing nature of the water.

Finally, while yeast nutrients aren’t part of your water profile, they are very important to making hard seltzer. As mentioned previously, the yeast won’t have nutrients from other sources when fermenting the sugar water.

To add yeast nutrients you can purchase nutrient kits from many brewing supply sites or add them yourself.

If you decide to add them manually, you will want to add free amino nitrogen or FAN, zinc, magnesium, and several other vitamins such as thiamin and biotin.

How do you find your water profile?

Now that we have the end goal in mind, we need to figure out where you’re starting from. Once you know your starting water profile you can decide to switch water sources or figure out how to tailor your current one.

There are three basic options for finding your water profile:

  • Do it yourself
  • Contact your water provider
  • Bring in a professional

Do it yourself

Testing your water yourself is relatively simple with a kit.

One thing you’ll need to keep in mind when looking for a kit is whether or not it tests for brewing specific factors. A good brewing water test kit will test for: bicarbonates, calcium, chloride, sulfate, magnesium, and sodium. A pH reader is also very helpful for homebrewing.

Most kits will come with instructions on how to perform each test and interpret the results. 

Contact your water provider

When you’re using tap water for homebrewing you can reach out to your water provider.

They will routinely check their water. These reports should be available online or by request. The only issue with this method is that the water provider might not check for the specific minerals you need to build a proper water profile.

On the plus side, you don’t have to spend money on a kit or send a water sample to a lab.

Bring in a professional

Sending a water sample to a professional testing service will get you detailed results. However, depending on the service you go with, they can be expensive.

Quality testing done by professionals is worth it if you don’t have the time or feel confident in your skills.

How important is the water profile in brewing?

You may be on a budget and wondering why you need to figure out your water profile at all. After all, how much of an impact can it have?

To a homebrewer just starting, water is just water. It’s not something to think too hard on. Experienced homebrewers, however, know just how important water profiles are. 

When homebrewing hard seltzer, water profiles are doubly important.

The water profile of hard seltzer is important because an improper profile can stall fermentation through low pH. After fermentation, it can also affect the end clarity and flavor. Adjacent to water profiles is fermentation-specific additives such as yeast nutrients.

In beer brewing, the effects of water profiles are certainly important, but there is a little more leeway. For example, during fermentation, the yeast can typically get pH buffering elements from the wort without an issue. 

When making hard seltzer, the “wort” is just sugar water unless you add chemicals or nutrients. This wort deficit can make it harder for the yeast to fully ferment the sugars.

Additionally, as the yeast ferments the “wort,” the pH will naturally decrease. If it gets below roughly 4.2 before fermentation is complete, the fermentation will slow to a stop.

Fermentation will also stop if the yeast cells do not have the nutrients they need to reproduce and continue converting sugar into alcohol.

Minerals present in a beer wort will buffer this pH drop and prevent it from making the environment unsuitable for yeast. Though there are some cases where you will need to add buffer minerals. 

Certain types of water profiles will have suitable minerals, but in most cases, you will have to add them manually. Specific minerals to add will be discussed later on.

All of this is just for the fermentation stage. The water profile used in hard seltzers will also affect the final product.

If the water profile is too hard, your final result may have a sharp solvent-like taste. Additionally, if it has too high of a mineral concentration it may appear cloudy and yellowish. All of which is off-putting in a hard seltzer. 

How do you adjust your brew water profile?

Once you’ve figured out what sort of water profile you’re working with, it’s time to adjust it to match your needs.

Water profiles can be adjusted with various salts and chemicals depending on the necessary adjustments. Use sodium bicarbonate to raise the pH by adding alkalinity, calcium sulfate to lower the pH, or calcium chloride to lower the pH and balance the chloride to sulfate ratio. Potassium metabisulphite can be used to eliminate chlorine and chloramines.

If you are starting with anything other than distilled or reverse osmosis (RO) water, you can use these brewing salts to adjust the profile levels as needed. 

When starting with distilled and RO water you are building a profile from scratch.

Each of the chemicals listed above will adjust your water profile whether you are starting from nothing or an existing water profile.

The amounts involved in adjusting will vary greatly depending on the existing profile. In general, you will not need much to achieve a good profile for hard seltzer. If you find you are needing large amounts you will want to consider using distilled or RO water.

What is the best water to start with for hard seltzers?

If your tap water is free from harmful chemicals and is close to a Dublin-style water profile, that will be the best water to start with.

As this is often not the case, the best water to start with for hard seltzers is reverse osmosis or distilled water. Both types of waters will have no other minerals or chemicals that might affect your seltzer.

Any other water source will need to be analyzed first so that you know what sort of water profile you are working with. This step is simple, but it is an extra step and can cost additional money. 

Both RO and distilled water can be bought from your local grocery store. Distilled water is roughly a dollar per gallon. RO water is similar in price.

There are ways to make both distilled and RO water at home. Home filtration systems and water distillers are the most common methods.

If you plan to make plenty of hard seltzer or have other uses for either water it would be beneficial to purchase a water distiller.

What to add to RO or distilled water to make a hard seltzer

It’s easy to create a good water profile when you start with a blank slate.

To create the best water for your hard seltzer:

  • You can use a pre-made water profile kit and adjust as needed or follow a recipe.
  • For an average 5-gallon batch of hard seltzer, add 1.5 gm of baking soda, 1.25 gm Epsom salt, and 1.25 gm magnesium chloride.

With hard seltzer, you’ll want to add alkalinity so that the pH doesn’t drop too quickly. Sodium bicarbonate (baking soda) will do this well.

The Epsom salt will lower the pH enough that the yeast can get started. The magnesium chloride will add some yeast nutrients.

Be sure to keep an eye on your brew’s pH levels and fermentation state. Further adjustments may be needed on a case-by-case basis.

Pre-made water profile kits are available on many home brewing supply sites. Not all will have one specific for hard seltzer.

What makes a good hard seltzer?

In the end, you want to make a hard seltzer that you will enjoy. There are some characteristics that contribute to a good hard seltzer no matter the taste of the drinker.

A good hard seltzer needs to be light, refreshing, clear, and moderately carbonated. Lightness comes from a low alcohol taste. Great water will provide a refreshing nature as well as clarity. Carbonation can be achieved by either priming sugars or forced carbonation.

Because homebrewed hard seltzers have so few elements – water, sugar, yeast, yeast nutrients, flavorings, and carbonation – each element needs to be perfected. 

Since water has already been covered, let’s briefly dive into how to improve each characteristic.

It is not difficult to make a hard seltzer that tastes light. Hard seltzers are light because of the lack of gluten and other calorie sources present in beer. 

When homebrewing hard seltzer there isn’t much you’ll need to do to keep this lightness. However, the flavoring you include can influence this. 

As a general guideline, it is best to use a light touch when flavoring your hard seltzer. Too much can be overwhelming and if using a flavored syrup can bring an undesirable syrupy taste.

The other undiscussed characteristic is relatively simple to do well. Carbonation through priming and bottling or forced carbonation, either one will give your seltzer a nice texture.

One benefit of forced carbonation is that the equipment can also be used for CO2 scrubbing. 

This process involves running carbon dioxide through your brew without the intention of carbonating.CO2 scrubbing is a great way to remove unwanted yeast flavors.

Bottle conditioning on the other hand can provide more natural carbonation. Additionally, it does not require additional equipment if you already bottle your seltzer.