Viscometer passes pizza sauce test

Edited by the Engineeringtalk editorial team May 9, 2008

The researchers concluded that the Hydramotion viscometer gave very stable readings and the lowest standard deviation of all the instruments used.

The XL7 on-line process viscometer from Hydramotion came out best in a comparative study of pizza sauce viscosity measurement methods carried out by a team at University College, Dublin.

The researchers were looking for a reliable method of determining the viscosity of pizza sauce continuously during manufacture in order to be able to assess the benefits of on-line measurement compared with the industry standard off-line standards.

Viscosity is directly related to the flow characteristics of the product, influencing such characteristics as pumpability, pourability and spreadability.

Sauce viscosity has traditionally been measured using rotational viscometers or consistometers, but the researchers found that these off-line techniques were time-consuming and could be subject to a degree of operator influence.

On-line viscosity measurement offers a number of advantages, including continuous real-time analysis, improved process control, less chance of operator error and lower labour costs.

The food processing environment presents a number of challenges to viscosity measurement, including hostile process conditions and the complex and often unpredictable rheological properties of fluid foods.

The Hydramotion XL7 online viscometer is ideal for such applications, as it combines ease of cleaning in place with minimal risk of fouling and meets strict sanitary requirements.

The researchers installed an XL7 in the pipeline between the sauce production "kettle" and the storage vats.

Sauce samples were also taken from the vats for off-line consistometer measurements and the results of the various methods were compared for repeatability, variability and stability.

In their report, the researchers concluded that the Hydramotion viscometer gave very stable readings and the lowest standard deviation of all the instruments used.

They noted that "The Hydramotion readings gave relatively tight output ranges and had the least inherent variability".

The XL7 was also foudn to easily capable of measuring all sauces encountered and capable of handling the particulates suspended within the pizza sauces .

Two sauces were out of specification and the Hydramotion viscometer was capable of picking out these out-of-spec sauces when this occurred.

The clean-in-place solid-rod sensor has a very hygienic design, with a crevice-free all-welded 316 stainless steel construction which eliminates the risk of material entrapment.

The measurement technique deters material build-up on the sensor but has no effect on the fluid.

Although the XL7 has very high sensitivity, it naturally rejects plant noise and vibration and is unaffected by fluctuations in flow or the presence of bubbles or solid particles.

There are no moving parts, seals or bearings that may wear out or fail in service, so maintenance is minimal.

"Once installed, the Hydramotion viscometer required little or no operator input, unlike viscosity readings obtained from the rotational viscometer".

Subjectivity and errors due to operator variability were removed.