Every CO2 supplier we could find in the St Louis area (Missouri) was checked one by one, and 15 of them made the list. 2 will refill the cylinder you walk in with. 6 only swap it for a different tank, which matters if yours is new or an odd size. 7 would not confirm either way, so those are marked call to confirm rather than guessed at. 2 confirm food grade CO2 for anything you actually drink; the common sizes here are 5lb, 20lb, 20oz; most cover welding, soda, homebrew.
15places listed
2confirmed refill
2confirmed food grade
Last checked September 2026
Sorted for you: places that refill your own tank come first, then the most complete, confirmed listings. Exchange-only and unconfirmed spots follow.
KeyRefillBothExchangeConfirm
Missouri Malt & Mill
Refill
2275 Cassens Dr #126 · Fenton, MO 63026
ServiceRefill
Food gradeCall to confirm
Tank sizes20oz / 5lb
Your cylinderYes, refills yours
homebrewsodaaquarium
Hours Wed-Fri 10:00-18:00; most Sat 09:00-16:00; Sun-Tue Closed
Official current catalog explicitly lists CO2 Filling & CO2 Cylinders and publishes kent@momalt.com for orders. Recent St. Louis community evidence from January-February 2025 confirms same-cylinder filling, including an actual 20 oz fill and current 5 lb pricing. Exact broader size support and food-grade designation were not verified. Additional service evidence: https://www.reddit.com/r/StLouis/comments/1i2uqpb
Official current site verifies the active Valley Park location, hours, phone, and branch service email. Recent St. Louis community evidence from February 2025 confirms CO2 same-cylinder filling, including an actual 20 oz fill and current 5 lb pricing. This fire-protection business is included only because current CO2 cylinder refill service is independently confirmed. Food-grade status was not verified. Additional service evidence: https://www.reddit.com/r/StLouis/comments/1i2uqpb
Official current CK Supply product pages explicitly label 5 lb and 20 lb CO2 as EXCHANGE ONLY and list O'Fallon, Illinois for pickup and walk-in exchange. The email is CK Supply's official general address rather than branch-specific. Food-grade status was not established for these exchange cylinders. Additional evidence: https://shop.cksupply.com/products/5lb-carbon-dioxide-exchange-only ; https://shop.cksupply.com/products/20lb-carbon-dioxide-exchange-only
Official current CK Supply product pages explicitly label 5 lb and 20 lb CO2 as EXCHANGE ONLY and list O'Fallon, Missouri for pickup and walk-in exchange. The email is CK Supply's official general address rather than branch-specific. Food-grade status was not established for these exchange cylinders. Additional evidence: https://shop.cksupply.com/products/5lb-carbon-dioxide-exchange-only ; https://shop.cksupply.com/products/20lb-carbon-dioxide-exchange-only
Hours Mon-Fri 07:00-17:00; Sat 08:00-12:00; Sun Closed
Official current CK Supply product pages explicitly label 5 lb and 20 lb CO2 as EXCHANGE ONLY and list St. Louis for pickup and walk-in exchange. The email is CK Supply's official general address serving its branches. CryoGas CO2 at the same 5835 Manchester address is part of the same physical operation and is not duplicated. Food-grade status was not established for these exchange cylinders. Additional evidence: https://shop.cksupply.com/products/5lb-carbon-dioxide-exchange-only ; https://shop.cksupply.com/products/20lb-carbon-dioxide-exchange-only
Official current CK Supply CO2 exchange product pages explicitly include Villa Ridge as a walk-in location for both 5 lb and 20 lb EXCHANGE ONLY cylinders. The email is CK Supply's official general address rather than branch-specific. Food-grade status was not established for these exchange cylinders. Additional evidence: https://shop.cksupply.com/products/5lb-carbon-dioxide-exchange-only ; https://shop.cksupply.com/products/20lb-carbon-dioxide-exchange-only
Official current CK Supply product pages explicitly label 5 lb and 20 lb CO2 as EXCHANGE ONLY and list Wood River for pickup and walk-in exchange. The email is CK Supply's official general address rather than branch-specific. Food-grade status was not established for these exchange cylinders. Additional evidence: https://shop.cksupply.com/products/5lb-carbon-dioxide-exchange-only ; https://shop.cksupply.com/products/20lb-carbon-dioxide-exchange-only
16835 Chesterfield Airport Rd · Chesterfield, MO 63005
ServiceExchange
Food gradeYes
Tank sizesAsk when you call
Your cylinderExchange only
sodabeverage
Hours Mon-Fri 08:00-16:30; Sat-Sun Closed
Official current M&H site lists the Chesterfield St. Louis location, supplies bottled Beverage Grade CO2, and describes a system of changing high-pressure bottles for soda systems, supporting exchange classification and food_grade=yes. Official sales email is companywide and serves this location. Current local listing supplies the branch phone and hours. Exact cylinder sizes were not published.
Official current Helget site lists this St. Louis physical location and explicitly supplies beverage-grade Carbon Dioxide. Coordinates and local phone are supported by a current local business directory for the exact address. Public portable-cylinder refill versus exchange behavior and sizes were not established. The official contact page provides a form and phone contacts but no reliably published general email address.
Official current branch page verifies the location, branch-specific email, phone, hours, and explicitly lists carbon dioxide among available specialty and medical gases. The page does not establish portable-cylinder refill versus exchange behavior, food-grade status, or supported sizes.
Official current branch page verifies the Alton location, branch-specific email, phone and hours, and explicitly lists carbon dioxide among gases available at this exact branch. Portable refill versus exchange behavior, food-grade status, and supported cylinder sizes were not established.
Official current branch page verifies the Pacific location, branch-specific email, phone and regular hours, and explicitly lists carbon dioxide among gases available at this exact branch. Portable refill versus exchange behavior, food-grade status, and supported cylinder sizes were not established.
Current Airgas branch evidence verifies the active Bernard Street store; current Airgas location materials identify carbon dioxide among gases at the St. Louis operation. The email is Airgas's official general customer-service address rather than branch-specific. Portable refill versus exchange behavior, food-grade status, and cylinder sizes were not established.
Official current branch page verifies the active Cahokia retail gas and welding location, phone and hours. A current branch-specific business listing for the exact location explicitly lists Carbon Dioxide among products. Linde's official general contact email is used because no branch-specific public email was found. Portable refill versus exchange behavior, food-grade status, and cylinder sizes remain unknown.
Linde Welding Gas & Equipment Center - Saint Charles
Call to confirm
2227 1st Capitol Drive · Saint Charles, MO 63301
ServiceCall to confirm
Food gradeCall to confirm
Tank sizesAsk when you call
Your cylinderAsk
weldingindustrial
Hours Mon-Fri 08:00-16:00; Sat-Sun Closed
Official current branch page verifies this Saint Charles retail gas and welding location, phone and hours. Current Linde location materials support industrial and specialty gas availability; the corporate Linde Direct email is used because no branch-specific public email was found. Portable refill versus exchange behavior, food-grade status, and supported cylinder sizes were not established.