You’re halfway through a stir-fry sauce and the recipe says cornflour. The pantry has arrowroot. Question: do they swap one-for-one?
Short answer — no, and the difference matters more than you’d think. Most sources call for slightly less arrowroot than cornflour (around two-thirds, though some recipes work fine at a 1:1 swap), and never let an arrowroot sauce hit a rolling boil. Cornflour likes a quick simmer; arrowroot likes the heat lower and the cooking shorter. Get those two things right and they’re interchangeable in 90% of recipes. Get them wrong and dinner turns to glue.
This is the bit most recipe blogs skip past. Here’s the proper version.
Cornflour (cornstarch in American recipes) is the pure starch milled from the endosperm of corn kernels. It’s bright white, almost weightless, and feels squeaky between your fingers — that’s the sign it’s pure starch and not blended with maize meal. In Australia you’ll see it as Coles Cornflour 300g for around $1.35, or White Wings Cornflour Gluten Free at the same size for about $3.40. Both work the same way.
Arrowroot is a starch too, but extracted from a tropical root — Maranta arundinacea — that’s been cultivated for cooking for thousands of years across the Caribbean and tropical Asia. It’s slightly off-white, fluffier, and has a faint earthy smell when you open the canister. You’ll find it in the baking aisle at most supermarkets (McKenzie’s is the common Australian brand) — noticeably pricier per kilo than cornflour, since the small packet sizes work out around twice the unit cost.
Different plant, different molecule shape, different behaviour in the pan. That’s the whole story.
This is the part to actually read.
Cornflour reaches its full thickening close to a simmer and turns sauces cloudy, almost milky. It’s structurally sturdy at simmering temperatures but breaks down if you reheat the sauce too many times — that gluey, watery split in yesterday’s leftover gravy is cornflour giving up. It’ll also seize and clump if you tip it dry into hot liquid, and it breaks down faster than arrowroot in long-simmered acidic sauces — the ones with vinegar, lemon, or a lot of tomato.
Arrowroot is happiest below a simmer — somewhere in the 75–85°C window — and stays glassy clear. Pour it into a fruit glaze and you can see through to the strawberries underneath, which is why it’s the patisserie default for tart toppings and clear pie fillings. The catch: arrowroot loses its grip if you bring it to a hard boil or hold it at heat too long. The starch chains break down and the sauce thins out within ten or fifteen minutes. Get the gravy off the heat once it’s thickened.
There’s one more practical difference. Arrowroot copes with acid better than cornflour, so it’s the right call for vinaigrettes, citrus glazes and tomato-based sauces where you’d want clarity.
| Original recipe says | Use this much | Notes |
|---|---|---|
| 1 tbsp cornflour | 2 tsp arrowroot | Arrowroot is slightly more powerful, so use roughly two-thirds. |
| 1 tbsp arrowroot | 1 tbsp + ½ tsp cornflour | Round up; cornflour is a bit weaker. |
| 1 tbsp cornflour | 2 tbsp tapioca flour | Tapioca behaves like arrowroot but needs more. |
| 1 tbsp arrowroot | 1 tbsp tapioca flour | Tapioca and arrowroot are close cousins — near-identical. |
Slurry the starch in cold water first (1 part starch to 2 parts water), then stir into the hot dish. Never tip dry starch straight into hot liquid — you’ll get lumps that won’t dissolve no matter how much you whisk.
Cornflour is the right call when: - You’re thickening a Sunday gravy or a chicken pie filling. Opaque is fine, even traditional. - You’re making custard, white sauce, or anything dairy-based. Cornflour works beautifully with milk and cream; arrowroot can go slimy in dairy. - The sauce will simmer for a while. Cornflour can sit at heat longer than arrowroot. - Cost matters. At a fifth the price per kilo of arrowroot, cornflour is the everyday workhorse.
Arrowroot earns its keep when: - You’re glazing a fruit tart, a Christmas ham, or anything where you want the surface to gleam. - The sauce is acidic — citrus reductions, tomato glazes, vinegar-based pan sauces. Arrowroot holds up where cornflour breaks. - You’re freezing the dish. Arrowroot survives freezing and reheating better than cornflour, which often goes watery once thawed. - You’re cooking for someone on a paleo or grain-free diet. Cornflour comes from corn (a grain); arrowroot doesn’t.
There’s a small catch on the dairy point. If a recipe specifically calls for cornflour in a custard or panna cotta, stay with cornflour. Arrowroot can develop a faintly ropey, almost slimy texture in cream-heavy mixtures. It’s not awful — just not the silky finish you’re after.
Both arrowroot and cornflour are naturally gluten-free. The difference is the supply chain.
Some cornflour is processed alongside wheat-based products and isn’t safe for strict coeliac diets, which is why you’ll see “Gluten Free” labelled explicitly on products like White Wings Cornflour Gluten Free — that label means the product was processed in a dedicated facility. The unlabelled house-brand cornflour at the bottom shelf is technically gluten-free by ingredient, but if you’re cooking for a coeliac, look for the certified label.
Arrowroot is more often packed in single-ingredient facilities, which makes it the easier default for anyone with coeliac disease. If you’re cooking for a coeliac guest and the cornflour in your pantry doesn’t have the gluten-free symbol, swap to arrowroot or tapioca and skip the worry.
Cornflour is grain-derived, so it’s out for paleo and Whole30. Arrowroot is the standard substitute in those cookbooks. Tapioca flour also qualifies (it’s from the cassava root, not a grain). Both arrowroot and tapioca thicken paleo-style sauces well — the catch is just remembering the lower heat window.
Australian supermarkets stock arrowroot inconsistently. Some Coles and Woolworths stores carry McKenzie’s; many don’t. If you walk in expecting it and walk out empty-handed, tapioca flour is the next-best swap.
Tapioca comes from cassava root, behaves almost identically to arrowroot in the pan, and stays clear in the same way. The substitution is roughly one-to-one (a touch more tapioca to match arrowroot’s strength). It’s also gluten-free, paleo-friendly, and tends to be easier to source through bulk-food retailers.
Graina stocks tapioca flour in our bulk range — it’s the same fine, off-white powder, sold by weight so you only buy what you need for a recipe rather than a 500g packet that lives in the cupboard for two years. See the tapioca flour product page for current pricing.
If you want to keep both arrowroot and tapioca on hand — useful for bakers and gluten-free cooks — store them in airtight containers away from heat and humidity. They’ll keep for two years if dry, but absorb moisture quickly and clump if left open.
Are arrowroot and cornstarch the same thing?
No. Cornstarch (called cornflour in Australia) is starch from the corn kernel; arrowroot is starch from the Maranta arundinacea root. They’re both pure starches and both thicken liquids, but they thicken at different temperatures and behave differently with acids, dairy and reheating.
Can I substitute arrowroot for cornflour one-to-one?
Not quite. Use about two-thirds the amount of arrowroot to replace cornflour — so 2 teaspoons arrowroot for every 1 tablespoon of cornflour. Going one-to-one will overthicken slightly.
Is arrowroot healthier than cornflour?
Both are nearly pure starch, so the nutritional difference is minimal — neither is a health food. The real differences are dietary: arrowroot is paleo-compliant and grain-free, while cornflour is grain-derived. Arrowroot is also the safer bet for strict coeliacs because of how it’s processed.
Does arrowroot work in baking?
Yes, but in small amounts. It’s used in gluten-free flour blends to lighten the texture and bind moisture. It won’t replace flour outright — it’s a supporting ingredient, not the main bulk. Most gluten-free flour blends use it at 10–20% of the total flour weight.
Why does my arrowroot sauce keep getting watery?
Two likely culprits. Either the sauce hit a rolling boil after the arrowroot was added (the starch chains break down past about 90°C), or it was reheated more than once. Add arrowroot at the end of cooking, take the sauce off the heat as soon as it thickens, and serve straight away rather than holding it warm.
Can I store cooked sauces thickened with arrowroot?
Arrowroot-thickened sauces freeze and reheat well, which is one of its quiet advantages over cornflour. Cornflour-thickened sauces often go watery after freezing. If you’re meal-prepping, arrowroot is the better choice for sauces and gravies you plan to portion and freeze.
So: cornflour for everyday cooking, arrowroot when clarity, acid-tolerance or paleo-compliance matter. If the recipe doesn’t specify, cornflour is usually fine. If you’re working on a glaze, a clear fruit sauce, or anything you’ll freeze and reheat, switch.
Goodness in grams.
Leave a comment