Science of Gastronomy: Sauce

• Sauces as an accompaniment provide different taste and texture to the food that we are eating. This in turn provides a new dimension to the food.
• Sauces can be of different viscosity/thickness. Making a good sauce is about achieving perfect texture and flavor.
• TEXTURE: Viscosity can be changed by adjusting the temperature, the type of solute, the size of the molecules in the solute (e.g. simple sugar vs oil) and suspended matter in the sauce (these can be particles, bubbles or oils). Difference between thickeners and suspenders is that thickeners combine with water to form a new substance which is usually translucent (think of a gelatinous starch solution) while suspenders do not form new substances. They are distinct from water and tend to settle down or float up when left alone for a while (think of vegetable particles settling down or oil floating up). Thickening with air as a suspender is in cappuccinos, or whipping creams/eggs. Egg whites can prevent disintegration of air suspenders.
• Corn starch and potato starch can be used as a thickener. Potato starch thickens faster than corn starch but it also disintegrates faster.
• Emulsifiers are things that are lipophilic and hydrophilic. Thus they can be used to mix these 2 together. E.g. using egg yellow to mix water and oil.
• So what makes an ideal sauce: it should be easy to pour out, it should be able to cover food it is poured on and it should not run in the plate. That is it should be less viscous when pouring but should thicken when poured.
• The concept of shear thinning and shear thickening comes into play here.
• FLAVOR: Flavor in sauces can be achieved using salt, alcohol, protein, starch and fat.
• Important to note. Decrease in viscosity leads to an increase in perceived saltiness. So for example, to use less salt (Hypertension Duh!!) increase the thickness of the sauce/soup. Thickness can be increased by adding larger molecules like starch or wheat flour. However, flour tends to bind salt. So for the same food item if we thicken using flour the food will have more salt content.
• Another ingredient to intensify the flavor of sauces is alcohol. Wines, brandy and vodka can be used to flavor sauces. Alcohol needs to be burnt out in the sauces. Just the flavor is used.
• Another ingredient in alcohol is protein which can come from egg yolk, gelatin and yogurt or cheese. Sometimes proteins bind to aroma and make it difficult to release it. Which is to say that the flavor will be diminished but because they release it slowly it may leave behind a slow aftertaste.
• Next ingredient in sauces is fat. Fat affects the creaminess of the sauce. Fat can be cream which is heavy or we can use a thinner form called emulsions. Fat in sauces cause the intensity of flavors to decrease but can make the flavors last longer. Which is to say that instead of very intense flavor for a short time, fat makes the flavor less intense but last for a longer time. Eg vanilla flavor lasts longer in full fat ice-cream. Fat is also used to extract flavors from ingredients like dried shrimp etc.
• Last ingredient in sauces is starch which can be corn starch, potato starch or flour. Lumping is a problem with starch. To avoid this we use cold water or oil to disperse the starch and then add hot water to dissolve it.
• Starch is known to reduce the flavor of the dish by either diluting the sauce or by binding to the flavor molecules thus hampering their release. This is also the reason why thin sauce is more intense for a shorter time while a thick sauce has less intense but the flavor lasts for longer.