What Is Clear Jel and Why Do Canners Swear By It?

If you've ever tried to use cornstarch in a home-canned pie filling, you've probably noticed something go wrong: the filling breaks down, turns watery, and sometimes doesn't set at all. This isn't user error — cornstarch simply cannot withstand the heat and acid conditions of the canning process.

During water bath or pressure canning, temperatures inside the jar exceed what cornstarch can handle. The starch granules break apart, losing their thickening power. What looked perfect going in comes out thin and separated.

Clear Jel is a modified food starch — specifically a waxy maize starch that has been chemically modified to withstand high heat, freezing, and acidic environments without breaking down. It was developed for exactly this use case.

The USDA's National Center for Home Food Preservation recommends Clear Jel as the only approved thickener for canned pie fillings. No other starch — not cornstarch, not flour, not arrowroot — has been tested and approved for this purpose.

There are two types: cook type and instant. Cook type must be heated to thicken — it's what you want for canning and stovetop pie fillings. Instant Clear Jel thickens without heat, making it useful for cold applications like no-bake fillings.

Crave Seasonings carries cook type Clear Jel, which is ideal for canning, baked pies, and any cooked fruit filling. Do not substitute one for the other in recipes — the thickening behavior is significantly different.

For most canned fruit pie fillings the standard ratio is 7 tablespoons per quart of filling for peaches, apples, and berries, and 5–6 tablespoons for more naturally thick fruits like cherries.

Always mix Clear Jel with sugar before adding to fruit to prevent lumping. Bring the mixture to a full rolling boil and cook for 1 minute before filling jars. The filling will look almost too thick at this stage — it thins slightly during processing and sets back up as it cools.

Clear Jel's stability makes it excellent for commercial-style gravies, fruit sauces, and glazes that need to hold up on a buffet or reheat cleanly. It produces a clear, glossy finish that cornstarch can't match. For bakers who sell at markets or do large-volume production, it's a professional-grade tool that makes a visible difference.