# Is tomato sauce shear thinning?

## Is tomato sauce shear thinning?

These fluids are called “Newtonian fluids”, and they come out of bottles in a pleasing manner. Tomato sauce and other non-Newtonian fluids don’t play that way: Others, like ketchup, are shear-thinning liquids — with agitation (a thumb on the glass ketchup bottle), they will thin.

What causes ketchup viscosity?

Fluids that have a constant viscosity independent from stress are called Newtonian. Ketchup explosions happen because when non-Newtonian fluids yield to pressure — squeezing, shaking, thwacking, etc. — and start to flow, the viscosity actually decreases the faster it flows. With force, a thick fluid becomes thinner.

Is shear thinning reversible?

In the majority of the liquids shear-thinning behavior is completely reversible, with the liquid returning to its ‘normal’ viscosity once the force is removed. If this relaxation is time-dependent then the fluid is called thixotropic.

### Does ketchup have a high viscosity?

Well, ketchup is a fluid with a high viscosity. Further, the viscosity of a fluid, such as ketchup, is affected by temperature.

Is ketchup considered a fluid?

This is because the ketchup is acting more like a solid than a liquid. Scientists actually call ketchup and fluids like it “soft solids” or “yield stress fluids” because they only flow when the right amount of force is applied. Ketchup is a soft solid because of its ingredients.

What is the shear property of ketchup?

Fortunately, ketchup also has an interesting shear thinning property. When an external force is applied in addition to gravity, the increased shear will result in decreasing the ketchup’s viscosity, allowing the product to flow more readily. This is why we sometimes must tap or shake the bottle to enjoy ketchup with our fries.

## Why does ketchup thin out when you shake it?

Shear thinning properties of ketchup are evident, especially during the [1,1.2] second interval when the bottle is shaken. Viscosity decreases, thus allowing more product to flow out of the bottle. Left: Viscosity measured along line 1 (see model setup above) at three different times.

What is shear thinning in fluids?

Shear thinning. Fluids that exhibit shear thinning are sometimes called pseudoplastics and are typically complex fluids such as blood, motor oil, ketchup, and even whipped cream, though simple fluids can also exhibit the behavior near their critical point (ex: xenon in Ref. 1).

Why does ketchup flourish?

This is the key to its curious behavior. As a non-Newtonian fluid, ketchup’s viscosity — and consequently its ability to flow — varies with the velocity gradient across the fluid or the shear rate.