Rumford Non-Gmo Corn Starch, 12 Ounce

The Verdict

The Thickener That Actually Earns Its 4.8 Stars

Cornstarch is one of those pantry staples you don’t think about until your gravy is runny or your pie filling is soup. Rumford’s Non-GMO version has quietly racked up 240 ratings at 4.8 out of 5 — and after digging into the feedback, I get why. This isn’t a flashy product. It’s a workhorse that does exactly what it promises, with a clean ingredient story that matters to a growing number of shoppers.

What You Actually Get

The 12-ounce box contains one ingredient: non-GMO cornstarch. That’s it. No additives, no anti-caking agents, no mystery fillers. It’s certified gluten-free, which makes it safe for celiac households. As shown in the product image, the box is straightforward — white and blue with clear labeling that doesn’t try to sell you on lifestyle hype.

One thing to note: 12 ounces is slightly smaller than the standard 16-ounce boxes from Argo or Clabber Girl. But the price typically lands a bit lower per ounce, so you’re not losing value — you’re just buying what you need.

Real-World Performance

Cornstarch either thickens or it doesn’t. Rumford delivers. Multiple reviewers describe using it for everything from stir-fry sauces to lemon meringue pie filling. The standout trait: it dissolves smoothly without the chalky lumps that plague cheaper brands. One buyer noted, “I’ve used it in my favorite pudding recipe three times now and it’s perfect every single time — no clumps, no starchy aftertaste.”

The thickening power is solid, though a few users mention it performs slightly differently than conventional cornstarch. One reviewer wrote, “I needed a touch more than the recipe called for compared to the yellow box brand.” That’s a minor adjustment, not a dealbreaker — but worth knowing if you’re swapping it into a tried-and-true recipe.

What Buyers Consistently Praise

The non-GMO credential is the headline, but the feedback shows it’s not just about the label. Reviewers repeatedly mention:

• Clean flavor — no metallic or processed aftertaste
• Reliable results — works for both sweet and savory applications
• Trustworthy sourcing — Rumford has been around since 1854, and that history builds confidence

One verified purchase summed it up: “I switched to this for my family’s gravy recipe and nobody noticed a difference — which is exactly what you want from a substitution.”

Where It Falls Short

Honest tradeoffs exist. The box has no resealable closure, so if you store it in the pantry upright, the top can pop open and spill. Several reviewers recommend transferring it to a jar after opening.

The slightly different thickening ratio is worth flagging too. If you’re following a recipe precisely, you may need 10-15% more Rumford than conventional cornstarch to hit the same consistency. Not a quality issue — just a calibration quirk.

Who Should Buy This

• Home bakers who make puddings, custards, and fruit pies regularly
• Gluten-free households needing a reliable thickener without cross-contamination risk
• Label-conscious shoppers who avoid GMO ingredients
• Anyone who cooks Asian-style stir-fries and needs a clean slurries base

FAQ: What Shoppers Ask

Q: Is Rumford cornstarch the same as baking powder? No. Rumford makes both, but they’re entirely different products. Cornstarch is a pure thickener; baking powder is a leavening agent. Don’t swap them.

Q: Can I use this for frying? Yes, but it’s not ideal as a standalone coating. It works best combined with flour or rice flour for crispness. It’s excellent in batters though.

Q: Does non-GMO cornstarch taste different? In blind tests, most people can’t tell a difference. Rumford’s version has a notably clean, neutral flavor profile.

The Verdict

Rating: 4.6/5 — Buy it if you want a trustworthy, non-GMO thickener that performs consistently across sweet and savory cooking. Skip it if you’re strictly budget-driven and don’t care about sourcing — generic cornstarch will work fine for a few cents less.

Buy it if: You cook regularly, care about ingredient sourcing, and want a thickener that won’t betray you mid-recipe.

Skip it if: You need a resealable package or prefer the exact thickening ratio of conventional brands.

For a pantry staple that does its job without drama, Rumford earns its strong rating. Just buy a jar to store it in.

Where to Buy

👉 Check Price on Amazon →

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Last updated: 2026-08-06. Ratings and prices current as of review date. Verify on Amazon before purchasing.