This article answers the most common questions surrounding the industry's preferred method for measuring flow rate and viscosity: The Bostwick Consistometer.

A popular choice throughout the food industry, the Bostwick Consistometer is typically found in sites that produce viscous materials and want to maintain high standards of quality and consistency.

Here at Klipspringer, we have years of experience supporting food factories in this area, so we are extremely familiar with the questions that surround this instrument.

With this in mind, we wanted to run through a list of the most popular queries – covering everything from How do you read a Bostwick Consistometer? to How do I clean a Bostwick Consistometer?

Below is a short video demonstration of Klipspringer’s Bostwick Consistometer. Alternatively, you can jump ahead to our list of frequently asked questions.

What are Bostwick Consistometers used for and how do they work?

Bostwick Consistometers are the preferred industry method for measuring the flow rate and viscosity of food products such as:

  • Jams
  • Soups
  • Sauces

Using this instrument, you can measure the distance a material travels under its own weight during a pre-determined time period. This allows producers of viscous products to establish set formulas for their product and to standardise production.

Is the Bostwick Consistometer food safe and what sizes are available?

Yes, Klipspringer’s Bostwick Consistometer has been designed with food production in mind. It is made from food-safe 361 grade stainless steel.

Our Bostwick Consistometers are available in three sizes: 24cm, 30cm, and 50cm. This allows you to select the correct size for your specific application and the viscosity of the products you are testing. If you are unsure about what size consistometer is best suited to your application, you can contact our in-house Technical Team on 01473 461800 or sales@klipspringer.com.

How do you read a Bostwick Consistometer?

1. Adjust the feet until the level bubble sits inside the marked circle, then make sure the gate is down and locked into position.

2. For accurate results, make sure the sample you are testing is at a constant temperature, then pour it into the reservoir. 

3. Using a knife or a similar straight-edged tool, remove any surplus sample. This should be anything that sits above the top of the reservoir.

4. At the same time, start a stopwatch and release the consistometer gate. Measure how far the sample travels during a pre-established time period. 

How durable is the Bostwick Consistometer?

As mentioned above, Klipspringer’s Bostwick Consistometer is made from food-safe 361 grade stainless steel. Because of this, it is extremely durable, suited the wear and tear of regular use at a food production site.

For improved strength and resilience, the instrument also features welded joints and a supporting bar for the adjustment screws.

In addition to this, the measurement lines have been etched onto the consistometer. As a result, they are more likely to stand the test of time, instead of fading away with frequent use.

How do I clean a Bostwick Consistometer?

Smooth and corrosion-resistant, stainless steel instruments are typically very easy to clean. Consistometers have the added benefit of being small in size and easily adjustable. With this in mind, it should be fairly straightforward for your operatives to wash out any residue and wipe down the equipment.

Even so, it is worth introducing images of ‘acceptable’ and ‘unacceptable’ consistometer cleaning to your Cleaning Instruction Cards, as this will help to set a standard for your team and will make life easier for operatives who don’t have English as their first language.

Manual cleaning brush used for hygiene tasks outside the CIP process

You could also explore our range of detail cleaning equipment, if your team would benefit from a brush that is small enough to reach inside the consistometer, with the bristle thickness to effectively clean the etchings.

Explore our range of Detail Cleaning Equipment

Cleaning Instructions

Clean your Bostwick Consistometer after every test using warm water (below 30°C) and a mild dish soap. Wipe carefully, avoiding heavy soaking of the spirit level. Dry thoroughly; even trace amounts of water alter friction and skew future readings. Ensure the gate and trough are completely dry before your next test.  

Daily Cleaning

  • Flush: Rinse out residue from the trough immediately after testing using warm water and standard dish soap. For stubborn, sticky substances, use a soft, non-abrasive detail brush.
  • Protect the Spirit Level: The bubble level is the only non-stainless component. Avoid soaking it, using aggressive chemicals, or blasting it with high-pressure water to prevent seal damage or fogging.
  • Dry Completely: Use a lint-free cloth or paper towel to dry the entire instrument. Moisture is the enemy of accurate testing, any remaining water droplets reduce friction, causing your next sample to flow faster and yield false readings.

Routine Care & Maintenance

  • Regular Level Checks: Before every use, level the consistometer by adjusting the feet until the bubble sits dead centre in the circular level. Periodically verify this with a separate spirit level placed along the graduated trough.
  • Handle the Gate Gently: The gate release mechanism and vertical tracks dictate your drop speed. Avoid slamming the gate or dropping the instrument, as bent tracks or misaligned gates ruin testing accuracy.
  • Professional Calibration: Ensure your unit stays compliant with ASTM Standard F1080 by having the manufacturer or accredited laboratories service and mechanically recalibrate it using a certified jig annually.

Proper Testing Workflow

A well-cared-for tool requires proper usage to last. Always ensure samples are at a constant, uniform temperature (e.g.(20°C) before testing. Fill the reservoir completely to the top, level off the excess with a spatula, and release the trigger.

What is the process for calibrating my Bostwick Consistometer?

Klipspringer’s Bostwick Consistometer is supplied alongside a calibration certificate. We also have an in-house, UKAS accredited laboratory that can manage any further calibrations over the years.

Another point to note is that Klipspringer consistometers each have a unique serial number for traceability, making it easier for you to keep track of your equipment and the relevant documentation.

You can then store your calibration certificates online using our Equipment and Calibrations Portal. This will allow you and the relevant team members to access your documents from any location, at any time. You can also set-up automatic calibration reminders, so you never miss a due date.

Explore our Equipment and Calibrations Portal

You now have the answers to the most common questions surrounding Bostwick Consistometers and the role they play in the food production industry.

If you require any further guidance, the Klipspringer team would be happy to help with your enquiries. You can contact us on 01473 461800 or sales@klipspringer.com. Alternatively, you can use the form below to arrange a consultation. 

If you would like further guidance relating to Bostwick Consistometers, the Klipspringer team would be happy to help. Share your details below to arrange a free consultation.