Saucy Science: Read This to Unlock the Key to a Perfect Sauce (and Pour) Every Time
Sauce is one of those things that is either really good… or really, really bad. There seems to be no grey area; it can do all sorts of strange things like congeal, curdle, and separate, but it can also perfectly coat your chicken wings or fries.
When I began to write this article, I realized I didn’t even know how to define a sauce. Is it a solid? Liquid? How does it work? As it turns out, they’re referred to as ‘soft solids’ in most scientific articles I’ve found. But it didn’t stop there – there’s so much to learn about what happens behind the scenes when a sauce is created… some things you may not even realize as you’re making it.
The water or fat in a sauce is what’s known as a continuous phase. This is the substance that allows for the molecules to disperse to create a soft solid. Once this has occurred, the concoction is then referred to as a ‘coarse dispersion’ or ‘suspension’. Examples of these in the food industry are mayonnaise, milk, and sauces like yours.
To illustrate how the process works, let’s imagine you have a pot of water – individual H2O molecules all swimming around in the same pot, but separate from one another, allowing the easy flow of the liquid (it would, of course, be super runny). Now let’s add some flour, whose molecules are naturally strung into a long and tangled shape. These flour particles “catch” the water molecules, grouping them together and creating a denser concoction. Suddenly, your water is less… watery. This is what happens as you add ingredients to your sauce.
How to get the perfect consistency every time
To get the consistency just right, we need to turn to rheology – a term coined by scientist Eugene C. Bingham which refers to the study of ‘soft solids’ (like ketchup and barbecue sauce) that are too thick to pour easily, but not so thick that they’re hard. I poured over a bunch of technical studies, and have learned that a sauce’s consistency boils down to three main components: shear stress, shear rate, and viscosity.
“Viscosity is a measure of a fluid’s resistance to flow,” explains one particularly informative study done by Sun Chemical Corporation back in 1995. Basically, when a semifluid like your sauce is set into motion, it moves in multiple layers. The shear force is what sets the fluid into motion to begin. The top, which is first to react to external forces like gravity (a form of shear force); and the bottom, which creates friction and slows down the sauce until it gains enough momentum to join the layers above. The shear rate is the difference between the speed at which the top and bottom layers move.
To thicken a sauce, you can use one of four solutions – particles, molecules, droplets, and bubbles. Here are some examples of each:
The science behind a customer’s perfect pour
Rheology can also teach us how a customer should pour their sauce to avoid being super frustrated or ending up with it splattered all over their shirt. According to this study, there are three steps to the perfect pour:
Step 1: Shake with the lid on. This mixes the ingredients so your customer doesn’t end up with the watery top layer all over their plate. It also loosens the sauce and sets the particles in motion.
Step 2: Turn the bottle fully upside down. This is a fairly obvious step which allows the sauce to flow to the mouth of the bottle.
Step 3: Tilt the bottle at the right angle, and tap it. “Start by pointing the open end of the bottle toward your food at an angle of around 45 degrees with one hand around the bottle neck, and the other delivering gentle but firm taps on the bottom of the bottle,” explains Anthony Strickland. Strickland is an expert in rheology, and a senior lecturer at the University of Melbourne. “Increase the force of the taps until you balance the force applied with the mechanical strength of the sauce in order to get it to flow.”
Deeply understanding your industry is integral to building a product customers will love. Get intimate with any subject you’re thinking of taking on – even if it means getting a bit saucy.
What type of sauce does your brand make? What went into its creation? Have you experimented with other types?