Large White Potato Starches, Thickeners & Gels

In Medieval times, sauces were made as reductions of broths from many ingredients, including beasts, fowl and game of all kinds. These broths were boiled down until thickened. Changing socio-economic conditions made this unaffordable, and chefs learned to make sauces from broths thickened with starches, mostly based on wheat flour.

In Asia, sauces were made on the fly in the last moments of cooking. The long cooking required with wheat flour obviously couldn't work, so other, purer starches came into use. These have been widely adopted for modern methods here in the West, for sauces, stews, soups and commercial products.

Non-starch thickeners have also come into use for special purposes, and some are gaining a presence in home kitchens.


Starch Thickeners

1.0Good all-around thickener, but with relatively strong flavor. It makes sauces glossy but somewhat cloudy. Liquid must be at boiling when added, but long cooking after adding will break it down, as will stirring while re-heating. Make a slurry with an equal amount of water before stirring in to avoid lumps. It does not take well to freezing and doesn't work well with acidic foods. It will do better if taken off the heat before acids are stirred in. 1 teaspoon will thicken about 1/2 cup of sauce.
Potato Starch2.0A good, powerful thickener, but its thickening power is quickly weakened by boiling. Add at the end of cooking and avoid boiling. In Chinese recipes, do not substitute for cornstarch where the coating is also the thickener for the sauce or you'll end up with far too much sauce. Potato starch thickened sauces reheat better than cornstarch thickened, but don't bring to a full boil. Potato starch is preferred for baking as it withstands higher temperatures. It is acceptable for Passover.
Sweet Potato Starch
Sweet potato starch is seldom used for thickening - it is used mainly for coating meats and vegetables for frying where a crisp surface is desired. It is sold in Asian markets as a powder and as granules for this purpose. It is also made into noodles.
Tapioca Starch2.0Thickens well at lower temperatures than cornstarch. It is often used to correct the thickness of a sauce at the last minute. Freezes well. Add to hot liquids at the last minute because it breaks down with heat faster than potato starch and a lot faster than cornstarch. No flavor and makes a clear but rather glossy sauce. Sub: instant tapioca (grind to powder unless you desire some texture); glutinous rice flour; potato starch (not for freezing).
Arrowroot1.5Flavor neutral and better for thickening acidic foods than cornstarch. Freezes well and is more resistant to breaking down from heat than cornstarch. It will thicken well below the boiling point so can be used for fragile sauces. It produces a clear sauce and the appearance is less glossy than cornstarch. It is relatively expensive but that's not really significant for home use. Arrowroot should not be used in dairy based sauces as it turns them slimy. It should be made into a slurry with cold water before adding to hot liquids.
Glutinous Rice Flour
Actually "gluten free", this thickener freezes well. Do not confuse it with regular rice flour. This flour can be sprinkled over simmering liquids and stirred in without clumping until you have the right thickness. Sub: tapioca starch.
Wheat Flour0.5A good thickener for sauces and gravies which does not make them look glossy (but also they will not be clear). Very stable and holds about the same as it cools. It thickens at boiling temperature and must be thoroughly cooked before or after adding. Most commonly this is done by cooking in butter to make a roux, but too much cooking will weaken its thickening power. A dark roux has very little thickening power. Cake flour has the most thickening power, bread flour the least, but all purpose flour is usually used.
Beurre manié0.5This is a kneaded mixture of butter and flour, but it isn't pre-cooked, so it must have sufficient cooking time in the soup or sauce.
Sago2.0Made from the inner pulp of a palm. Sometimes found in Asian markets. It needs to be cooked fairly long to develop its thickening power, but is thus rather heat stable. There is another Sago starch made from the inner pulp of a Cycad, but it is seldom found in commerce.
Kudzu0.7Kudzu flour will thicken at room temperature. Rare and expensive - Southerners would rather complain about kudzu than learn to use it. When cooking with kudzu it should be mixed with cold water before stirring into hot liquids and should be stirred well for a while as it has a tendency to sink to the bottom.
Sahlab1.0Made from the root tubers of an orchid grown in Turkey. Export is currently forbidden and most "sahlab" on the market is fake.
Instant ClearJel®
A modified corn starch much used for commercial pie fillings and similar applications. It thickens without cooking, is acid stable, stable at high temperatures and takes freezing well.
A modified corn starch much used for commercial pie fillings and similar applications. It is also much used in home canning as the only thickener approved by the USDA for canning applications (Instant ClearJel® is not suitable). Unlike Instant ClearJel® it is not usable where the product will be frozen.

Non Starch Thickeners and Gels

Guar Gum8.0Made from a South Asian bean, it's powerful but clumps like crazy. Best mixed with sugar or salt (whichever goes into your recipe) and stir briskly while adding. Some add through a salt shaker for better dispersal. Do not attempt to use as a slurry, it will clump. It will thicken at room temperature, but takes a long time so heat is often used. Prevents formation of ice crystals in frozen foods.
Xanthan Gum3.0This non-starch thickener is increasingly popular with the fancy chef set because its high thickening power allows it to be used in very small amounts which do not affect flavor. At room temperature it is an effective thickener at 1% concentration. It looses strength with heat so it's most used in room temperature or cooled applications. It has unique properties that make it particularly useful in salad dressings and chili sauces. It's made by fermenting sugar with a particular bacterium.

Made from seaweed, this is similar to gelatin, but stronger and gels without refrigeration. Approved for vegetarians. It can be substituted about 1:1 for gelatin. it is available in Asian markets. It does not work well with acid foods, or foods containing oxalic acid.
Konjac Flour

This white powder is a soluble fiber extracted from Konjac corms. It can gel at room temperature, has 0 carbs, nearly 0 calories, and is diabetic and vegan safe. It firms up more with wet cooking.
A natural gel agent found in fruit. It's main use is in the production of fruit jellies and jams.
Derived from seaweed (Chondrus crispus - Irish moss), this gel agent is widely used in commercial products, particularly dairy products such as yogurt or sour cream. This ingredient has been found to cause inflammation, even in the quantities used in commercial products, and it can possibly result in gluten sensitivity. It is best avoided.
A natural product of meat and fish released with heat. Commercial gelatin is made by boiling hides and bones of domesticated animals. Commercial gelatin is used mostly to produce gels and aspics. 1/4 ounce will set 16 ounces of liquid.
Formerly used as a thickener by almost all meat eating peoples (though forbidden by Jewish law), blood has fallen out of favor in "mainstream" (squeamish) North American societies, and is banned by law in some regions. Here in Southern California, tubs of blood (coagulated and non-coagulated) are widely available in Asian and other ethnic markets.

How Starches Work

Starches are long chains of glucose molecules. Glucose is a type of sugar. Unlike sugars, starches are insoluble in water or alcohol. There are two main types of starch produced by plants for energy storage, amylose and amylopectin. The animal form, Glycogen, similar to a highly branched amylopectin, is not considered here.

Plants store starches in crystalline form in granules. When exposed to heat and moisture these granules swell and burst, releasing the starch molecules, which unwind from their crystalline form to become amorphous and tangled.

Amylose is in the form of very long almost unbranched chains that tangle severely when released, thus amylose is a most effective thickener, entrapping large amounts of liquid among its tangled chains. When cooled amylose tends to become stiff.

Amylopectin forms short chains that are highly branched, not as effective as a thickener, but more effective at creating gels. When cooled, amylopectin does not become as stiff as amylose.

The proportions of these two starches greatly affects the cooking characteristics of starchy foods. Also the Glycemic index (of interest to diabetics) is lower for amylose than for amylopectin.

Rice, for instance, ranges from long grain with mostly amylose to short grain with mostly amylopectin. Long grain cooks up fluffy and relatively dry. When cooled it becomes stiff, a good start for fried rice. Short grain rice is mostly amylopectin and cooks up rather sticky. "Glutinous" or "sticky" or "sweet" rice is entirely amylopectin and cooks up very sticky indeed (and contains no gluten).

Potatoes are another example, ranging from russets with mostly amylose to round whites, high in amylopectin. Russets stay dry and fluffy, excellent for baking and mashing but fall apart with boiling and other wet cooking methods. Round whites boil up firm and hold their shape in soups and stews. Others are in between.

Starches come from two main sources: seeds (wheat flour, cornstarch) and roots or tubers (potato starch, arrowroot). The amylose chains of root starches are longer than those of seeds, thus potato starch is a more effective thickener than cornstarch.

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