Monday, June 25, 2018

Carbonating Water: Making Seltzer at Home

Pouring a glass of carbonated water from the tap!The only dedicated tap on our kegerator is the one for carbonated water. All beverages are marked up when you buy them by the serving rather than in bulk, but carbon dioxide dissolved in water is one of the most egregious. Making 5 gallons at home costs less than a dollar. When it comes to bottles, smaller is better because after opening the bubbles begin to escape. Having it on tap ensures the water is always ideally carbonated, and wonderfully cold (especially compared to our 75F/24C summertime tap water).

Seltzer, sparkling water, fizzy water, and bubbly water are synonyms, referring to water with carbon dioxide bubbles. In the US, "mineral" water is required to have 250 parts per million total dissolved solids (TDS), usually from a natural spring. Club soda or soda water is similar, but usually has the minerals added to it. Adding quinine (from cinchona tree bark) would turn it into tonic water. I don't think there is any need to get technical when making your own.

Luckily the process to carbonated water at home couldn't be simpler, if you already have a kegerator. Fill a keg with good tasting water (e.g., carbon-filtered tap water, reverse osmosis) and connect to a CO2 tank. Set your regulator for between 20-30 PSI, depending on how strong you want the bubbles to be. Once the keg is connected vent the head-space and then let the water chill and the CO2 infuse. To speed things up, once the water is chilled, you can shake the keg to speed up the absorption of the gas. Cold water can hold onto CO2 much easier, so you're wasting your time to shake room temperature water.

We add a small dose of chalk (calcium carbonate) to move our tap water closer to the profile of Perrier. Chalk doesn't readily dissolve at water's roughly neutral pH, but it is happy to once there is carbonic acid in solution. This is essentially the same thing that happens with acid rain meets limestone, the carbonic acid dissolved in the rain eats away at the calcium carbonate in the rock.

My Treated Water



The calculator on this site includes many more profiles if you have a favorite mineral water.

If you are a fan of flavored seltzers like Polar or La Croix, you could add a small dose of a natural flavoring of your choice. It is best to dose a glass to taste and then scale up, a little goes a long way when it comes to these super-concentrated "natural" flavorings like those from Amoretti. You can also use actual natural ingredients like citrus peel. In that case I'd remove those after hanging them in the keg for a day or two. If you stick with plain water there is no need to clean or sanitize between fills, but with strong flavors you may need to clean if you are switching flavors.

This post is also available in video form on my YouTube channel.


Unknown said...

I too like to keep soda water on tap. I like mine with a twist of lemon or lime.

When my kids want a sweet treat, I let them make flavored soda. 2 cups of water, 2 cups of sugar, and 2 tbsp of any flavoring extract. Their two favorites are coconut soda and almond soda. Add an oz of the syrup to the soda water and it's good to go.

They have been known to lug a couple of jars of soda flavor and my small kegerator down the local farmer's market in lieu of a lemonade stand.

The Mad Fermentationist (Mike) said...

Very nice! Our two-year-old niece has become a fan of plain carbonated water, although the excitement of pouring it is the main attraction it seems.

Florin said...

Presumably, oxidation isn't an issue here. So, are you purging the headspace just to make sure it's only CO2 being dissolved into the water?

The Mad Fermentationist (Mike) said...

Exactly. Pure CO2 will dissolve into the water more quickly than a mix of gases thanks to partial pressure laws. If ~40 % of the gas in the headspace is nitrogen from the air, the effective CO2 pressure will only be 60% of what it would be with pure CO2.

ethan said...

Do you keep the keg at 20-30 PSI or drop it lower for serving?

The Mad Fermentationist (Mike) said...

I maintain the pressure at ~25 PSI. You could certainly go up to 30 PSI to speed up carbonation, and then lower it a little for serving, but too far and the water will slowly get less carbonated.

Dave said...

I had that Amoretti sample kit sitting around so I thought I'd give a try making flavored seltzer. I think we spend $10 a week on flavored Polar at our house, so it'd sure be nice to make my own. I went all the way up to 100x the suggested dosing rate for beverages, but still didn't get much flavor. This was the Mango water-soluble extract (suggested .01-.02%, I gave up after .25oz in 16oz). Any tips?

James said...

If I ever get a keg setup I think I will get a small keg and experiment with carbonating my favorite wines. It occurs to me that some cocktails might also benefit from some extra carbonation.

The Mad Fermentationist (Mike) said...

Dave, maybe you just aren't sensitive to the aroma compound? I put a drop of the Mango extract into an 8 oz glass of carbonated water and it was more than enough for me. Sort of reminded me of kid's tropical toothpaste.

I've been to a few bars that have pre-blended cocktails on tap (makes it easy for the bartender). Works well if you are drinking through the keg quickly, but at home you'd want to make sure it'd hold up for as long as you expect the keg to last.

Unknown said...

My tap water run usually has a pH of around 8-9. If I add the 10 grams of chalk required to meet the Perrier ion content wouldn't the final product be over the top basic? Maybe I'm missing something.

The Mad Fermentationist (Mike) said...

The carbonic acid will provide the balance. You can certainly start with just carbonated tap water as a baseline and then add the chalk to the second batch to compare.

Unknown said...

Very interesting. The still water went into my keg at a pH of 6.5 and, once carbonated, read at 4.0.
What prevents beer from having such dramatic acidification during the carbonation process?

The Mad Fermentationist (Mike) said...

It does, we just read and discuss the final pH of degassed samples of beer.

smallbbrewer said...

I find that I go through so much more fizzy water than beer!
I now have a selection of fruit juices, syrups and chopped up fruit to throw in.

Thanks for the mineral profiles on creating specific 'styles' of water, thats a step I haven't taken yet!

Unknown said...

was that about 5 grams worth of chalk you added to the water? how much would you add to RO

The Mad Fermentationist (Mike) said...

About 1.5-3 g of chalk per gallon of RO will get you in the same ballpark for calcium and carbonate.

SoCoBrewer said...

Getting some white cloudiness after about 2 days of carbing - will a little time solve that?

The Mad Fermentationist (Mike) said...

If you added chalk it may not have dissolved, give the keg a shake now that there is CO2 in solution.

Anonymous said...

I carb my waters through the liquid tube to avoid manual labor and yet provide agitation at the bottom of the keg.

Chema said...

Do you think I can flavor my water with some essential oils?


The Mad Fermentationist (Mike) said...

You'd likely need to add an emulsifier (like soy lecithin) to prevent the oil from separating from the water and floating to the top of the keg. Not something I've tried. Generally water-based flavors are a better bet.

jmo said...

Really appreciate this video. It was super informative and has given me a nice break during the hot season (I live in Thailand). We played around with this for a bit and had some really successful kegs. However the past few have not been carbonating well. I'm wondering if you have any advice.

We have recently added 2g NACL and 2g baking soda as well as some McCormicks flavoring (3-4 teaspoons). Even after force carbonating, sitting in a fridge for 10 days with CO2 at 25psi, the water is really foamy, but doesn't hold any of the carbonation after the foam dissipates. We also have found that some of our beers aren't carbonating well as well so I'm not sure if it is a leak, or too much sodium bicarbonate, etc. The batches that worked well didn't have McCormick's in it. I will try the next batch without to see if that helps. Really appreciate any advice you might have.

The Mad Fermentationist (Mike) said...

A longer (or narrower) serving line to the tap can help to prevent too much CO2 break-out.

We haven't dosed in any flavorings to our water, but I don't think that would effect carbonation retention anyway. Generally the most important factor there is the viscosity of the liquid. Water even with salts or flavorings should have similar viscosity as you add so little I would think.

Best of luck!

Unknown said...

Fantastic website and video. Thank you. Very entertaining. Question -- what size CO2 bottle do you use and how many 5 gallon kegs of carbonated water can you make? Would you expect the volume of fizzy water to be less than the volume of beer for the same CO2 tank size? I tried looking in the video to see if I could spot a 5 or 10 lb CO2 tank but I could not see it.

The Mad Fermentationist (Mike) said...

I've got a 20 lb tank that I use for both beer and water. Typically lasts me about a year of drinking (two people plus friends). Carbonated water will use roughly twice as much CO2 per keg because it is carbonated and served at ~25 PSI vs. ~12 PSI for beer. So I'd expect half as many kegs of water compared to beer from the same size tank.

Blake Wavell said...

Hey dude, this video is awesome! I'm not much of a homebrewer, but I sure love good beer...and am using your video to set up a beer/water double-tap in a kitchen at our house. Are you carbonating the water and beer from the same CO2 tank? If so, what's the schematic? separate pressure regulator for each line or something?

The Mad Fermentationist (Mike) said...

I have a dual regulator that can output different pressures. One side goes to a manifold for the beer at ~12 PSI and the other goes directly to the keg of carbonated water. You certainly could do a line of secondary regulators for each keg if you'd prefer.

Optimus Prime said...

Do you think it is necessary to first boil the water before kegging it?

The Mad Fermentationist (Mike) said...

No, we go right from the filter into the keg. With the low-oxygen environment in the keg we've never had issues with microbial growth or anything.

ItsMe said...

Do you use star san or any other keg sanitizer or cleaners? Trying to see if that no rinse sanitizer will affect the taste of water.

The Mad Fermentationist (Mike) said...

Maybe once a year I'll run StarSan through the keg/line. Never had it cause flavor issues.

Sparkling said...

Hey thanks for sharing this! I was wondering how long you leave the keg hooked up to the CO2 at 30PSI. Can you eventually lower it to 12PSI and leave it like that? Thanks!

The Mad Fermentationist (Mike) said...

You'll need to leave it at high pressure or the water will eventually become less carbonated as you pour it. Nothing wrong with less carbonated water if you prefer it that way though!

Unknown said...

I've had this web page saved on my phone since January and it took a long time for a filter that I can run through a hose to arrive. We must have spent $200 on soda stream cylinders this year and I never would have thought of this. Finally have the water kegged and chilled next to the beer with a dedicated tap and line and just purchased a secondary regulator so we can run the beer too. Looking forward to it and very grateful for the article. Gary in NZ

Sanga said...

I have added tap water to 5gal keg and hooked Co2 at 32psi. The water temp in the keg is at 22c. Reading the carbonation chart it says to get 2.4 carbonation level at 22c i will need 32psi.

I have tried a shake method and using quick carb pump and carb stone but no co2 is dissolved in my water. Anything i'm not doing correctly?

Anonymous said...

Do u want them having so much sugar

Joshua C said...

Just wanted to throw my experience into the ring here in case it will help anyone:

Been brewing beer for years and just recently took a stab into the world of making sparkling seltzer at home and after several batches I can solidly say that both myself and my family are overwhelmingly pleased with the results.

We decided to just go with regular, unfiltered tap water and we fill each keg with some ice (to keep the temp as low as possible to have the c02 absorb more quickly into solution) and then fill with the water on top of that.

If we're just going with regular seltzer, we throw it on the gas at about 30 psi for roughly a week until it's fully carbed or we can shake the keg for about 15 minutes if we need it sooner. Once the carbonation is at the proper volume we jack the gas back down to 10 psi to serve.

If we want it flavored, we go with flavor extracts and add them directly to the keg to taste from the dropper. This was the hardest thing to dial in properly over time.

Roughly, we found that about 7-8 drops per 12 oz of sparkling water was where we felt the flavor should be at for each extract we tried (but it's all up to your personal preference, obv) which led us to around 400 drops per 5 gallon keg of water and once we figured out how many drops were in a normal, full suctioned 'pull' from the dropper we dosed the kegs accordingly. For us, we would get ~25 drops per 'pull' so it came out to 16 full 'pulls' per keg of extract, but of course YMMV.

Pro tip - If you're waiting for the keg to carb over time and keep tasting it to see where it's at as it goes along, don't be alarmed if the flavor is a tad sharp at first. Once it's fully carbed the flavors meld and even out nicely.

Hope this helps someone out who's on a similar sparkling water journey, and good luck to you all!

Optimus Prime said...

Thanks for this write. I’ve always wondered if it’s worth the hassle to boil the water before kegging so it might lay longer…and I’m also wandering how long tea would last if I purge the head space and used 2-3psi, just enough to get it to seal the lid. I don’t mind the minimum about if bubbles in tea…and I could also use nitrogen to push the tea.