Liquid laundry starch was originally designed to make it easier to smooth fabrics while ironing, leaving clothes and linens crisp and wrinkle free. Commercial starches have a long list of ingredients, including water, cornflour, cyclocarboxypropyloleic acid, sodium hydroxide, sodium tetraborate, tetrasodium edta, castor oil, sodium hyroxymethylglycinate, dimethicone, sodium metabisulfate, fragrances and dyes. Homemade liquid starches can be made with just water and cornstarch, although you can also add a few drops of an essential oil if you'd like to scent your starch.
Liquid Starch Recipe
To make liquid starch, you'll need 4 tablespoons of cornstarch and 4 1/2 cups of water. Combine the cornstarch with 1/2 cup of cold water and set aside. Bring the remaining 4 cups of water to a boil; stir the boiling water into the cornstarch and water mixture. Allow the starch to cool, then add two to three drops of essential oil if you'd like to scent the starch. Transfer the starch to a spray bottle. Add more water if you'd like a lighter starch; reduce the water if you'd like a stronger starch.
Both commercial and homemade liquid starches are made primarily of water. Tap water will generally be fine to make the starch, unless your tap water has a high mineral content which tends to leave iron or rust stains. If that's the case, you may want to use distilled water to make sure the starch doesn't stain your clothes.
Cornstarch is made from ground kernels of corn and is used to thicken liquids. Powdered cornstarch clumps when combined with hot water, so you need to blend the cornstarch with cold water first. After the cornstarch is thoroughly dissolved, it will thicken, rather than clump, when the boiling water is added. Cornstarch is organic and an attractive food for pests, so do not store clothes and linens after they have been starched.
While the liquid starch will do a fine job of smoothing out wrinkles during ironing if it is made from just cornstarch and water, it won't have the "fresh scent" that commercial liquid starch leaves on your clothes. If you'd like to add a fragrance to your homemade laundry starch add two to three drops of an essential oil, such as lavender or lemon oil, after it has cooled.