Sour cassava starch (sour tapioca starch)

Although both Sour and Sweet Cassava Starch are derived from cassava, their versatility allows for varied results in cooking. Therefore, understanding the particularities of each type is the first step to achieving the authentic structure of traditional Brazilian cheese bread (Pão de Queijo).

What is sour cassava starch?

Sour Cassava Starch (commonly marketed in the US as Sour Tapioca Starch or Fermented Tapioca Starch) is cassava starch that has undergone a natural fermentation process. This fermentation alters the chemical structure of the granules, granting them distinct expansive properties when exposed to oven heat. It is important to note that, despite the name, the starch is not actually sour in flavor, just as the “Sweet” variety is not sweet; these terms refer solely to the production process and the resulting functional properties, not the taste.

During production, the starch is kept in water tanks, where natural fermentation occurs. This process is exactly what sets it apart from the sweet variety. The chemical alteration resulting from this procedure allows for more pronounced structural expansion during baking, which is essential for creating the characteristic internal air pockets and a crispier crust in Brazilian cheese bread recipes.

It acts as the primary leavening agent in the dough, responsible for the lightness and the aerated internal structure.

Texture control:

While sweet cassava starch provides density and softness, sour cassava starch is the secret to that crispy exterior and hollow (alveolated) interior structure.

The balance:

Combining both types of starch in a pão de queijo recipe is an excellent strategy to achieve the ideal balance of textures. By mixing the two, you get the best of each: the softness and density provided by sweet cassava starch, combined with the rise, lightness, and crunch characteristic of sour cassava starch.

Where to find sour cassava starch in the US?

It is primarily found in the US under the labels Sour Tapioca Starch or Fermented Tapioca Starch. You can buy it at Brazilian, Latin, or Asian grocery stores, as well as online platforms like Walmart.com or Amazon.