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Manufacturers and distributors of specialist equipment for the agricultural, environmental and building industries.

Potato Dry Matter Measurement

Weltech Digital Dry Matter Weigher
Potato Dry Matter Field Kit
Zeal Hydrometer

Three Methods of Dry Matter Testing

Potato Dry Matter Field Kit
(Product code: POT/DMK or POT/DMKSAL)

The Potato Dry Matter Field Kit is supplied in a sturdy carry case with high accuracy scales, corer, penknife, filter papers and calibration chart.

A pocket-sized kit to test dry matter of individual tubers quickly and simply in the field.

The dry matter kit works by taking a core from a pre-cut tuber, weighing it very accurately and converting the weight  to percentage dry matter using a calibration chart.

The kit demonstrates the dry matter variability within samples and in the same field. Results can be compared with a bulk average method by taking multiple readings and averaging them.

Available with standard ware corer (Product code: POT/DMK) and both ware and salad variety size corers (Product code: POT/DMKSAL).

Zeal Bulk-Average Hydrometer

Zeal HydrometerA traditional dry matter weigher used extensively throughout the potato world by producers of crisps, French fries, potato wedges and canned, frozen and powdered potato products.

A simple and accurate method of measuring specific gravity and percentage dry matter of potatoes.

A known weight of potatoes is placed in the basket and the Zeal Hydrometer and basket are suspended in a large container of clean water. The buoyancy of the unit in water determines the water level against the vertical scale and hence gives the dry matter reading.

  • Suitable for static applications
  • Requires a clean metal or plastic container at least 350mm dia. x 660mm deep. When filled with tap water (approx. temperature 15°C/60°F), the instrument with basket attached must float freely. A 45 gallon/175 litre drum or plastic bin is ideal.
  • Potato weight needs to be exact (3.63Kg/8lbs)
  • Supplied with sample basket and calibration weight

Available in 3 dry matter ranges:

Model D4500 (Product code: POT/HYDROMETER)
17 to 25% Dry Matter; 1.065/1.110 g/ml specific gravity

Model D4501 (Product code: POT/HYDROMETER4501)
14 to 23% Dry Matter; 1.055/1.095 g/ml specific gravity

Model D4502 (Product code: POT/HYDROMETER4502)
18 to 27% Dry Matter; 1.070/1.114 g/ml specific gravity

Weltech Digital Dry Matter Weigher PW-2050

PW-2050 Digital Dry Matter Weigher (the basket & chain is optional and should be ordered separately)The Weltech Digital Weigher automatically calculates the dry matter content, starch percentage and specific gravity of potatoes using the weight in water method.

A precise and easy to use method of measuring specific gravity, starch and dry matter percentage of potatoes. The weigher can store up to 5000 individual weights in its memory. To download data we recommend the version with USB port and memory stick (thumb drive).

The PW-2050 is battery operated and will continue to work for up to 12 hours between charges.

The instrument is suitable for normal use, and for testing potatoes in French Fry production. Neither type requires an exact sample weight.

  • Requires a container with just a 40cm depth of water.
  • Portable, simple to use and robust. Stores data for PC download.
  • Supplied with strong carry case and battery charger.
  • Includes basket & chain



Models available:

PW-2050 (Product code: POT/HYD/DIG)
Weight range: 1.5 – 6Kg of potatoes (must not exceed 10Kg)

PW-2050 USB (Product code: POT/HYD/DIGUSB)
Weight range: 1.5 – 6Kg of potatoes (must not exceed 10Kg)
USB output and memory stick (thumb drive)

The Importance of Dry Matter

Dry matter content directly influences the yield of processed potatoes,  the oil absorption rate in fried products and also the texture of cooked potatoes. Dry matter is also used as an indicator of bruising risk, with high levels associated with more damage.

Dry matter varies  between varieties but dry matter of the same variety may also vary between seasons in the same locality. This can be the result of differences in the time of planting, soil moisture and ambient temperature.

Typical dry matter ranges for various potato products*:

French Fries – 19.7 to 24.1%

Potato chips – 21.7 to 25.1%

Dehydrated products – 20.7 to 24.1%

* guidance only

Comparing dry matter measurement methods

The three methods of measuring dry matter all have specific design benefits to
suit different types of use

Dry Matter Field Kit

  • Highly portable
  • Compact
  • Does not need water
  • Uses individual tubers to create a genuine average
  • Low cost method
  • Needs care in use to ensure accuracy

Zeal Manual Hydrometer

  • Simple to use
  • Accurate
  • Fast results
  • Static use only
  • Needs a large water container
  • Potato samples must be weighed precisely

Weltech Digital Hydrometer

  • Precise and easy to use
  • Instant results
  • Needs only a small water container
  • Portable or static use
  • Does not require a precise weight of potatoes
  • Data storage and download facility

All three dry matter methods have been independently and scientifically compared by potato industry bodies. No significant differences were found between the three methods in their estimation of dry matter content.

For more information on our full range of Potato Quality Equipment, click on the button
below to download the brochure

Click on the title below to find out further information

Electronic Potato      Potato Hot Box      Glucolis Potato Sugar Testing

Potato Harvester Mister      Potato Temperature Monitoring      Potato Quality Control

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