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The Ultimate Guide to Homebrewing Hard Seltzer

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!

BrewChatter Hard Seltzer Watch the pH

What Makes a Hard Seltzer So Difficult to Ferment??

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!!

Water Modifiers for buffing your water

Buffing the Water

First and foremost, we need to address the water profile.  If you just use your normal tap water or ditilled/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. 

Fermaid O Yeast Nutrient

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.

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.

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.

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 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!

Clear Homebrewed Hard Seltzer with Lemon

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, the Super-Kleer K.C. 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.

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.

Elderberries Fruits and Flavors

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 homebrewer in all of us!

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, Twitter and Pinterest 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!  Don’t forget to join our BrewChatter Newsletter to stay up to date on cool new products, videos, and BrewCranium posts!  Brew On!! . 

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R.J. - July 21, 2020

Hi Nikki! Baking soda will definitely help! Keep an eye on the pH as fermentation begins, and if fermentation pH drops below that 4.2 line, you can add a little more to get it back up. Make sure that you’re using plenty of Fermaid as well!

Nikki - July 21, 2020

Hey! This was super helpful, thank you! Trying to brew my first batch this weekend but confused about how to regulate the pH of the water – starting with UV water, so a pH of 6. Will lime/lemon juice do the trick? Or baking soda?

R.J. - July 8, 2020

Hey Gina! Congrats on your first seltzer! Try some Super Kleer or Gelatin in the next one to help everything clear out, and that will help with the yeasty characteristic. Also, time in the fridge will help alleviate those flavors. Make sure that you’re starting with plenty of yeast nutrients and buffers so that the yeast can finish the job. Let us know how the next one comes out!

Gina - July 8, 2020

Hi! So brewed for the first time ever! Used a hard seltzer kit. Long story short the yeast was stuck after the 3rd day tried a bunch of things ended up pitching new yeast,! Batch finally fermented ready to drink, but the end product tastes a bit yeasty or like beer! Any advice for future batches?

R.J. - July 1, 2020

Hey Joanna! You sure can! At this point, especially if it’s clear, you can bottle it and carbonate it, or keg and carbonate it, and it will be a very similar product to cider or hard seltzer, although it might not be as clear. The only real difference is that you’re adding the carbonation, and if you want to add any other flavor to give it a little more zip!

Joanna - July 1, 2020

I have some grapefruit wine sitting in a carboy but it isn’t quite the flavor I was hoping for. I am wondering if I can make it into a hard seltzer from this point? Can I follow a cider recipe maybe? Thank you!

R.J. - June 22, 2020

Hi Brent! A little more robust, 5.7 – 5.8 like you said, from the start doesn’t hurt at all. Make sure that you don’t go above 6.0. The pH is going to fall down either way, so the trick is making sure that there is enough buffer in the water so that it doesn’t fall too far below 4.2 – 4.3 during fermentation. They will still work slowly below 4.0, but they don’t like it much and the finished product tastes tart and sharp.

R.J. - June 22, 2020

Hey Sarah! There is a simple formula for dextrose per gallon. 1 pound of dextrose in 1 gallon of water will give you a gravity of 1.042, and because it’s a simple sugar, you can expect that the finishing gravity will be 1.000. That means that 1 pound in 1 gallon fermented out will give you an abv of 5.9%. Using this as a baseline, you should be able to shrink or scale to whatever size batch you want to brew!

Brent - June 22, 2020

So what is your suggested starting ph? That wasn’t totally clear from the post. Are we talking something like 5.2-5.3 or are you looking for something more robust in the 5.7-5.8 range?

Sarah - June 22, 2020

Is there a simple formula for amount of dextrose per gallon of water to give 1% alcohol? I know it is slightly variable with yeast efficiency but many of the recipes I am reading are conflicting, and I want to know so I can make any volume of seltzer not just the standard 5 gallons.

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