A consistometer is an instrument that measures viscosity, or thickness, of a tomato product. This simple device is the most accurate way to conduct a flow test so you can quickly determine whether you need to make adjustments to your recipe. Need a thicker sauce? No problem! With a consistometer, you’ll always have the right tomato thickness for every dish.
Viscosity is the measurement of the flow rate or thickness of a tomato product. Usually, the higher the concentration of the product, the thicker it is. The thicker the product, the better the yield, which equals a more desirable product for the restaurant operator. We measure viscosity with what’s called a consistometer, also known as a Bostwick Consistometer. It’s a low-cost, durable, stainless steel instrument that uses very little space, but it’s the simplest, most accurate way of conducting a flow test.
The unit is engraved with a series of graduations at 0.5cm intervals all along the bottom of the trough, which is separated near one end by a spring-loaded gate. This creates the chamber where the sample being loaded will be tested. Before you start, you want to make sure that your unit is on a flat, level surface. Opposite the chamber, there’s a bubble level which can be used to make sure that the unit is level. Two screws opposite that on the other end can be used to adjust up and down, to make sure that your unit is level.
To run the test, first, close and lock the gate with the lever arm in the up position. Next, you’re going to fill the reservoir up to the top with the product being tested. Don’t forget to level off the top. Make sure that the chamber is full and contains no air pockets. Next, you release the product at the same time that you start a 30-second clock. Go ahead and stop the clock and observe how far the product has travelled down the trough. For us, we’ve got about a 6.4.
Consistency is a measurement of how material flows against itself because of the force of gravity. Therefore, when the gate is released, the sample begins to drift down the trough. The distance travelled in a fixed length of time is known as consistency. In 30 seconds, a thicker tomato product will travel less distance than a thinner. Thicker equals a lower Bostwick reading. In our training case, our Bostwick reading was 6.4cm. By following these steps, we can identify the thickness of any tomato product, like we did today with our San Benito tomato sauce.