The Ultimate Guide to Homebrewing Hard Seltzer
Ok, Ok, Ok, I know there are some purists out there who think this whole Hard Seltzer fad is ridiculous. I know you’re out there because until very recently, I was with you! Don’t get me wrong, something light and refreshing to take to the beach is always a good thing, so I was never a hater, just not a total believer. But now that everybody has a hard seltzer, including some of our favorite craft breweries like Imbib and Heretic, I thought we should at least try this whole thing out.
What I found out was that it is not as easy as it should be! There’s a ton of science happening here, and it’s taken quite a few experimental fermentations to get our Hard Seltzer Kits simplified and tasting great. This week is all about hard seltzer, the surprising amount of science behind it, and how you can make sure that your seltzer ferments, whether you’re brewing 5 gallons or 30 barrels!
The simple answer is pH and available nutrients. If you’ve tried making your own hard seltzer, you know that within a day or two, fermentation just stops. It seems like it’s for no reason until you throw a pH meter on it, then it all makes sense.
In alcoholic fermentation, sugar is broken down to pyruvic acid, and from there broken into ethanol and CO2. With so few nutrients and minerals in a hard seltzer, since it’s really just dextrose and water, the yeast are only capable of making so much ethanol before the pH slams down below the level where they are capable of working. This is because a lower pH literally changes the structure of the amino acids in solution, and the enzymes that they use to break them down are no longer effective. These are the main issues in making a seltzer, so let’s fix them and make some seltzer!!
Buffing the Water
First and foremost, we need to address the water profile. If you just use your normal tap water or distilled/RO water, fermentation pH is going to drop like an anvil in a Warner Bros cartoon. We have to add some carbonates and bicarbonates to the water profile to counteract the acidic profiles that are going to be created. We started with a high gravity stout kind of profile, a little like Dublin’s water, then pretty much doubled up on CaCO3 and baking soda when it still wasn’t enough!
The trick when building your water is not to get the pH high, but to give the water the minerals that it needs to combat acidic compounds as they are released into solution through fermentation. Your yeast, whatever strain you choose, has no interest in being in a pH that’s higher than 6.0, and prefers to be closer to 4.5 or 4.6. That means that when we build the water, we need to have enough buffer in there so that by the time fermentation is done, we’re sitting around 4.2. This is not only for fermentation, but if you’re too far below that, your seltzer takes on a distinctly tart flavor profile, and might mess up your whole balance.
Our preferred method for this is to start with R.O. water, or distilled, and build everything from the ground up. If you’re savvy with water and water profiling, you can easily build your tap water up to a profile where you’re buff enough to handle this super simple glucose fermentation.
If you are a DIY spirit, like most of us who home brew, here are a few things that we've tried successfully before we landed on the mixture of mineral additions in our BrewWater Yeast kit.
For a fruited Peach seltzer, we tried adding approximately 7 tablespoons total over the course of fermentation, of Burton Water Salts to a 5 gallon batch, which actually made a wonderful, fruited peach seltzer. While this worked out pretty well, fermentation did start and stop and drop pH quite a few times (hence the 4 total additions of Burton salts!), and needs to be re-visited adding in the total amount with the pitch of yeast. The pH ended a little low, but ended up balancing really well with the peach flavor from the Peach Wine Base.
Another, more promising, experiment, was adding in a packet of our BrewWater Water Profile Kit - Malty Stout and High Gravity. Fermentation was pretty consistent, although it still needed a little CaCO3 bump to increase the pH a little to get the last few points down. This one was a fresh lemon lime seltzer that came out fantastic! The fix here was building a similar water profile, again super similar to the Guinness water profile, but adding in some extra baking soda and a little extra calcium chloride to this already robust profile to give it just a little extra pH buffer.
Feed Me Seymore!
Going into a fermentation with basically nothing available, you need lots of delicious, high quality nutrients to get things started and keep things going. If you’re using our BrewWater Hard Seltzer Water Kit, buffing the water and adding nutrients is all already handled, but let’s explore what kind of nutrients we really need for this kind of fermentation profile for those of you who are a little more DIY and adventurous.
To get started, we need lots of nitrogen. This promotes cell replication and fermentative metabolism. This will give our yeasties the boost that they need to handle multiplying enough to eat all of the sugar that’s in solution.
For this part of the process, we use a little bit of Diammonium Phosphate, commonly known as DAP. This puts available nitrogen directly into solution that the yeast can easily uptake and use to build their mass up and start budding. If you prefer a more organic approach, consider using White Labs Servomyces, which is a more natural nitrogen source, and just as effective, if not more so.
Next we need a full spectrum yeast nutrient that has absolutely everything that the yeast will need during the fermentation, and ‘yeast energizer’ isn’t going to do it! For us, Fermaid O is the way and the path. The ‘O’ stands for organic, and this is one of the cleanest and most comprehensive yeast nutrients available. We’ve had amazing luck on beer, wine, mead and cider with Fermaid O, so it’s a no brainer to use this in something with absolutely nothing to hide behind…. because it’s basically carbonated alcohol water. You can also use Fermaid K, which is Kosher instead of organic, but we've found that Fermaid O lends itself towards helping the yeast produce less sulfur compounds.
Usually, we follow the directions given by the manufacturer and add in the Fermaid at 33% sugar depletion, but we’ve found through testing that in this type of fermentation, it’s best to give the yeast all of the nutrients from the get-go. It seems a little counter-intuitive, especially if you’ve been brewing for a while, but think of it this way: in a seltzer, there’s even less nutrients in solution than with a mead, which is notorious for not having any nutrients in solution.
Basically, we have to set our yeast up the right way, which means we have to add all of the nutrients that we would have otherwise added to solution at the beginning, and make sure that they’re dissolved in before the yeast even have the chance the touch it. Per 5 gallons, start with 20 g of DAP (or 2 servomyces tablets) and 30 g of Fermaid O. That’s been the sweet spot for us, so far.
The only other note on nutrients is that if you don’t add everything at the beginning, some stuff gets left behind, and you can definitely smell it! We had one batch that we did that, before adding flavoring, was like drinking a nice, carbonated batch of Fermaid O! Surprisingly, not as bad as it sounds, but also not great!
Crushing Them With Clarity
The clarity thing is more about patience than anything. If you’ve attempted this type of fermentation already, you know how it comes out. Cloudy, not quite milky, with a little bit of off-color haze. It seems like it will never clear, and you’re pulling off of the keg for weeks when, one day, all of a sudden, you have a clear, perfect seltzer.
For whatever reason, all of this stuff just stays in suspension. Think of it like when you fill a bucket of water from your hot water heater and it’s cloudy from the build up of all of the minerals in the heater. Same concept.
Faster solutions are around, but if you’re not adding an extra additive, then plan on 3 - 4 weeks for natural clarity. As far as faster solutions, these are the two best that we’ve found.
First, our Super Clear Fining Kit seems to be able to clear anything and everything, from stubborn wine and cloudy, pectin-filled ciders to Hazy IPAs. This stuff is pretty unstoppable, even though it says it’s not great for hard water or pectins, because it targets both negative and positive ions in two different stages. This means it runs the gambit on making things stick together, get heavy, and fall out. This stuff is the real deal, and has no problem clearing up your seltzer in about 48 hours!
For a more natural, and maybe more sciency approach, try pitching some White Labs Clarity Ferm when you pitch your BrewWater Hard Seltzer Yeast Kit. This will enzymatically clear everything, especially with a proper crash chill.
Fruits, Flavorings, or All of the Above?
Of course, the answer is all of the above! What we love about using the Fruit Flavorings is they are easy, fast, and you can really come up with some stellar combinations, as seen in our 5 Gallon Hard Seltzer line of recipe kits. These are all high quality and natural flavorings, so no worries about your seltzer tasting fake unless you add too much. You TRULY know the flavor I’m talking about if you’ve been tasting seltzers available on the market! The other benefit of the flavorings is that you want to make a chocolate-banana-marshmellow seltzer, well, you can do that!
The cool thing about adding fresh fruit or puree is that, well, it’s fresh! It’s a little harder to work with, especially if you are bottling your seltzer, but think of adding fruit more like a back-sweetener than something you ferment with. The added sugar in the fruit is what you’ll use to get the fruit flavor (remember, fruit flavors are attached to the fructose in the fruit).
The other fun thing about adding fruit is playing with it and trying to find the proper balance, which I think appeals to the home brewer in all of us!
Update 9.9.20 - A Note on Carbonation
Some of you who keg your seltzer may have noticed that it can be hard to find the balance between properly, almost over carbonated, seltzer and getting it to pour like anything other than a firehouse out of the faucet. A quick tip from one of our customers who makes tons of seltzer using our recipes, is probably the simplest thing ever, and I can't believe I didn't think of it!
He carbs his seltzers fairly high, around 3.3 volumes or so, but found that he got huge head when he poured, and his seltzer wasn't staying as fizzy as he wanted. So all he did was add in a Carbonation Lid! So simple and easy, and the same fix that we've seen used for pouring kegged Cold Brew Coffee!
This is effective because the carbonation lid has a 2 Micron Diffusion Stone attached to an extra Gas-In Post on the lid. This makes sure that all of the CO2 going into solution is in the form of super small bubbles, increasing the surface area of the gas exponentially, and making sure that it gets into solution. Very cool science, and a super simple fix if you've run into this! Also a great tool to have to carbonate just about any fermentation in 24 hours!
Update 10.1.20 - Step by Step Selzter Instructions
We've had tons of emails from our DIY home brewers that want to craft their seltzer with fruits and flavors that they already have on hand, so we wanted to post up some simple step by step instructions for everyone that will work with our BrewSeltzer Kits, or with the sugar, fresh fruit or flavors that you have at home!
Step 1 - Use the Right Yeast!
Of course, the easiest option here is to use the BrewWater - 5 Gallon Hard Seltzer Yeast Kit. This packet already contains everything, including the yeast, that your seltzer needs to rock and roll with minimal effort!
If you want to experiment like we did and figure out your own Seltzer Yeast Kit, remember that you want to use a strain that is already geared towards simple sugar fermentation, like Prise de Mousse or another variant of the Champagne Strain like K1V-1116. These guys are super competitive, ethanol tolerant, and use nutrients efficiently.
Step 2 - Use the Right Nutrients
Traditionally, especially with mead, wine and cider, we will wait until day 2 or 33% sugar depletion to start adding nutrients, but in a seltzer, the yeast need those additions right away. Calculate what your total nutrient additions would be for the complete fermentation, and add all of it at once either when you pitch your yeast, or right before. This will give your yeasties everything they need right off the bat, and encourage them to use all of it so it doesn't linger in the finished product. We prefer Fermaid O and DAP, and use almost 25 g in our yeast kit.
Step 3 - Water Matters
For the sake of the end product and it's overall flavor and clarity, use distilled or reverse osmosis water! The idea here is to find the balance of pH by building your water profile to have plenty of salts and minerals to combat the acidity produced during fermentation, but not have so much that it lingers after fermentation has finished.
Build your water up using a classic Dublin water profile, something high in bicarbonates and calcium, but not so high in TDS (total dissolved solids) that you can taste an off flavor in the finished product and have clarity issues. The idea here is to give plenty of counter-balance to the production of acids and low pH.
Step 4 - Add Your Sugar
You don't necessarily have to boil your water for the sugar addition step, but it makes the sugar go into solution easier. That being said, especially if you are using clean, distilled water and a sanitized stirring utensil, no need to get crazy. Your sugar will go into solution.
For 5.5 gallons of Seltzer at 7% abv, use 6.5 lbs of dextrose, and for 5.5 gallons of 5% abv Seltzer, use 4.5 lbs of dextrose. This is an easy rule of thumb, and ensures that you will come out of fermentation with 5 full gallons of product.
Step 5 - Allow Fermentation To Finish!
Make sure that you give your seltzer 14 full days to finish fermentation and let the yeast clean up after themselves. This is paramount!
Step 6 - Fruits and Flavors
You have tons of options when it comes to fruits and flavors. It's no secret that we love the Fruit Flavor Extracts, but you can also add fresh fruit or fruit purees to fermentation and as a back-sweetener!
For Flavoring Extracts, you'll add the desired amount directly to your keg or bottling bucket, a little at a time until the flavor is where you want. For Fruit Wine Bases, you want to add these during fermentation, and we like to supplement with another flavor extract at packaging.
For Fresh Fruit and Fruit Puree, you can add these either during fermentation, as a back sweetener, or both! Adding at both times will give you the most complex and complete flavor profile for the fruit that you are using, but it's much trickier to bottle with so much extra sugar in solution. Head over to our article, My Fruit Wine is Done Fermenting...Now What, for a full run down on different methods of back sweetening with a more natural sugar.
Step 7 - Let's See Clearly
With everything that's in these seltzers, even though it doesn't seem like much, a good fining agent like Super Clear will do wonders for the finishing clarity. This will not only help it look like the alcoholic water you are trying to make, but also help your finished product taste cleaner and more neutral, bringing out the fruit or flavoring. You can also use Clarity Ferm when you initially pitch your yeast, which will also help everything clear up and give you a nice, clear finished product.
Step 8 - Carb It Up!
See our Update from 9.9.20 for some awesome tips on carbonating your seltzer! Lots of good trials and information there. Just remember that you want to carb a little heavier than you do on most of your beer or cider, adding a bit of extra carbonic acid to help bring all of the flavors to the forefront of the aroma.
Thank you all for reading, and I hope this helps you with your next hard seltzer! Post any questions you have below, and tell us about your experience making hard seltzer! If you want an easy, seamless seltzer, check out our line of Hard Seltzer Recipe Kits! Want to make your own, just not sure about the yeast? Grab a pack of BrewWater Hard Seltzer Yeast Kit, and worry about making what you want without having to science the whole thing start to finish!
Don’t forget to follow us on Facebook, Instagram, and Twitter to keep up on fun happenings, news, and more science! Follow us on YouTube at BrewChatterTV for even more fun, info and get to know us a little! Brew On!! .
Update 3.19.21 - New Advanced Seltzer Blog!
If you've gone through this article, but you're ready for the next step, head over to our Advanced Home Brew Hard Seltzer Brewing Techniques! In this article we cover stuck fermentations, elaborate on clarification, and even talk about getting rid of that funky sulphur smell in your finished product! Cheers!