Starch is a common substance, and many people don’t realise how often it is used when cooking. While it is found in basic products such as rice and potatoes, it is also used to bake and most often functions as a food thickener.
Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store.
Most starch is sold as a white, tasteless and odourless powder that can be dissolved in cold water or any other liquid.
How does starch work when cooking?
Starch powder consists of granules that swell and gelatinise when combined with water and heat. This process produces the thickening of soups and sauces.
The cooking process is essential to achieve the correct thickness. Undercooking will leave a starchy taste while overcooking and extensive heat exposure will often cause the starches to break down, resulting in thinning the sauce or soup.
How to store starches?
All starches are best kept in an airtight container that keeps out moisture, dust and insects. Keep them in a dark, dry, and cool place and always be aware of the expiration date on the package.
Different kinds of starch
This is produced from corn kernels that have been dried and ground. To use, dissolve the starch in cold water or any other cold liquid and add in small portions to soups, sauces and gravies to thicken the liquid. It will produce a translucent, glossy finish.
Be aware the corn starch, also called maizena, is pure and very efficient. Once it reaches the temperature (144–162°F or 62–72°C), thickening happens very fast. We don’t recommend adding starch undissolved into the food as it will form lumps.
Potato starch is extracted from potatoes. It is a fine white powder which gives a light potato flavour but when used in recipes, this flavour is undetectable. It is used in a similar way as corn starch to thicken liquids and also in baked recipes because it adds moisture to the recipe.
Tapioca starch is extracted from the roots of the cassava plant. It thickens ingredients quickly, and it also works well as a binding agent. It is a perfect substitute if you don’t have corn starch at hand. Tapioca starch is commonly used to thicken pie fillings, but will also work well in puddings or soups. A positive of tapioca is that it does not lose quality when reheating or freezing but on the negative side it will break down quicker than corn starch or potato starch when exposed to high temperatures.
Arrowroot is a tropical plant also known as Maranta arundinacea. The powder is extracted from the root, it has no taste and it becomes clear when it is cooked which makes it perfect to thicken a jus or clear sauces. It is less commonly used due to its high cost. Do not use it with dairy products because it will form a slimy mass. However, it works better than corn starch when thickening acidic foods. When a mixture starts thickening with the addition of arrowroot it should be removed immediately from the heat to prevent the liquid from thinning.
This product is made from ground raw rice. It is mainly used as a thickening agent in recipes that need refrigeration or freezing since it inhibits liquid separation. It’s recommended that you use twice as much rice flour as corn starch to get the same result.
Using flour as a thickener is a whole different way of working compared with the above-mentioned products. Flour needs to be cooked well to avoid the taste of uncooked flour in your dishes. It is usually mixed with butter, such as in a roux, and it is used to thicken sauces, often with dairy involved.
Kuzu is a high quality starch made from the root of the kudzu plant that is native to Japan and China. It is reputed to strengthen the digestive tract.
Kuzu’s root, flower, and leaf are used to make medicine and they have been used in Chinese medicine since at least 200 BC. Today, kudzu is used to treat alcoholism and to reduce symptoms of alcohol hangover, including headache, upset stomach, dizziness, and vomiting.
It needs to be dissolved in a cold liquid before adding it to anything hot. Stir constantly when heating until the milky white becomes clear.