Three sugars, one identical carbonation target, three different weights — and understanding exactly why those weights differ is more useful than just memorising the conversion ratios, because it tells you which sugar is actually the right choice for reasons beyond "whatever's in the cupboard."
The same batch, three ways
A 20 L batch at 70°F, targeting 2.6 volumes of CO2 — a fairly typical lager-strength target — needs:
- Corn sugar (dextrose monohydrate): 141.7 g
- Table sugar (sucrose): 127.6 g
- Dry malt extract (DME): 192.7 g
Check the corn sugar figure directly, and switch the sugar type dropdown to see the other two. Three genuinely different numbers, from a single unchanged target — the difference isn't rounding or approximation, it's each sugar's actual fermentable content expressing itself in the required weight.
Corn sugar: the formula's own baseline, and why
Dextrose monohydrate is the sugar this site's underlying priming formula (widely reproduced across homebrew software, commonly attributed to Kai Troester's published research) is built around — it's also simply the most commonly stocked and used priming sugar in homebrewing, cheap, reliably consistent, and completely neutral in flavour contribution. There's no strong reason to prefer anything else unless you have a specific one.
Table sugar: cheaper to find, needs less by weight, but comes with baggage
Granulated table sugar (sucrose) needs roughly 90% of the corn-sugar weight for the identical target — anhydrous sucrose carries no water of hydration diluting its fermentable mass, so gram for gram it's a slightly more concentrated fermentable source than dextrose monohydrate. It's also the cheapest and most universally available option, sitting in nearly every kitchen already. The trade-off some brewers cite is a theoretical risk of a very faint cidery note at high usage rates, though this is genuinely debated and, at the small quantities used for priming specifically (as opposed to using sucrose as a large fermentable adjunct earlier in the process), most brewers report no perceptible difference from corn sugar at all.
DME: needs the most by weight, but adds real character
DME needs roughly 1.36x the corn-sugar weight for the same target, because only about 65-70% of DME's weight is actually fermentable extract — the rest is unfermentable dextrins, proteins and other malt-derived material that contributes no CO2 but does contribute flavour, body and a touch of extra malt character to the finished beer. This is exactly why some brewers deliberately choose DME for priming despite needing more of it by weight and despite the extra cost relative to plain sugar — it's the only one of the three that adds anything back to the beer beyond carbonation, however subtle that addition is at typical priming quantities.
Why corn sugar became the default in the first place
Dextrose's dominance as the standard American priming sugar isn't an accident of homebrew tradition alone — it traces back to it being cheap, shelf-stable, and widely available through the same supply chains that already distributed it for other food and beverage uses, well before homebrewing had its own dedicated retail category. Once a critical mass of published recipes, priming charts and eventually software all defaulted to corn sugar as the reference sugar, it became the natural baseline everything else gets compared against — which is exactly the role it plays in this site's own priming formula, not because dextrose is chemically special, but because it's the sugar the underlying published research (and decades of homebrew convention built on top of it) was calibrated against.
The ratios hold regardless of batch size
It's worth confirming this isn't an artefact of the specific 20 L example above — the sugar-type ratios (roughly 90% for table sugar, roughly 136% for DME, both relative to a corn-sugar baseline) are fixed multipliers built into the underlying fermentability of each sugar type, not something that shifts with batch volume or target CO2. A 1-gallon batch and a 10-gallon batch targeting the identical CO2 level will show the identical proportional relationship between their three sugar-type doses, just scaled to very different absolute weights — see how much priming sugar for 1 gallon and how much priming sugar for 5 gallons for the small- and standard-batch versions of the corn-sugar figure specifically, both following the same ratios described here if you need to convert either to table sugar or DME.
A fourth option worth a brief mention
Honey and maple syrup can also prime a batch, and some brewers choose them deliberately for the character they add — but neither is a manufactured, standardised product the way the three sugars above are, and neither has a single reliable conversion factor the way corn sugar, table sugar and DME do. Real honey and maple syrup vary batch to batch in water content and exact sugar composition, so any conversion is necessarily an estimate rather than a precise figure the way the three sugars compared here are. See can I prime with honey or maple syrup for the fuller treatment of that specific question, including working estimates for both.
Why the ratios themselves are worth remembering, not just the results
If you ever need to substitute one sugar for another without a calculator handy — mid-brew-day, cupboard doesn't have what the recipe called for — knowing that table sugar runs about 90% of a corn-sugar weight and DME about 136% lets you convert a familiar corn-sugar figure on the fly rather than guessing. Getting this conversion wrong in the direction of using too little of a substitute sugar just leaves you flat and needing to wait longer or dose a small top-up later; getting it wrong in the direction of using too much is a genuinely different problem — see what happens if I use too much priming sugar for why that direction matters far more.
A caveat all three share
None of these figures accounts for CO2 already dissolved in your beer — every one of the numbers above already has that correction baked in, based on the temperature entered, but if you're doing a quick mental conversion between sugar types on brew day using only the ratios (rather than re-running the whole calculator), make sure you're applying the ratio to a dose that's already been correctly calculated for your actual batch temperature and target, not to some remembered rule-of-thumb weight from a different batch entirely. See priming sugar CO2 targets by style if you're not sure what target to start from before applying any of these ratios.
Picking one, in practice
For most brewers, most of the time, corn sugar is the sensible default — cheap, neutral, consistent, and the sugar every published ratio and every piece of brewing software treats as the reference point. Reach for table sugar when it's simply what's already in the house and you don't want a special trip for a bag of dextrose — the outcome is close enough to identical that the substitution barely registers. Reach for DME specifically when you want the small flavour and body contribution it adds, treating the extra weight and cost as the price of that character rather than an inconvenience to avoid. None of the three is "correct" in some absolute sense; they're three legitimate tools that happen to need three different weights to do the identical job of hitting a target carbonation level, and the right choice depends on what you're actually optimising for beyond the bubbles themselves.