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Grain tester
Pic GRAIN 17

Complete grain tester scale, Germany. The complete tester include:

A - measuring bucket
B - striking knife
C - suction cylinder
D - filling pipe
E - discharge cylinder
F - scale beam
G - weighted hanger
H - brass stand for the beam

The weights ( common knobbed weights ) are lost.




German Grain scales

Weighing grain today is a complicated business, but it was not always so. A long time ago, it was realized that buying grain by volume, like wine or milk, was inadequate. The usefulness of grain varied with the size of the seeds, their moisture content, the amount of dirt included, and the damage done by worms which hollowed-out the husks. Thus it was found necessary to weigh the grain in addition to measuring its volume. Rather than weighing all the grain, samples were taken from each sack, and tested for quality.

Using ordinary measures and scales, many imperfections were present. Inconsistencies in the capacity of the measures, and the different weights used in each town and country, made comparison difficult. Also, the density of grain put into the measure varied from user to user, according to his method of doing lt.

Recognizing these difficulties, the instrument-maker Gniser, Inspector for Berlin, introduced improvements for weighing grain, in 1781. He fixed standards for the whole of Germany, using the volume measure 1/8 Metze of Berlin (1/128 Scheffel), and the weight of 1 Krampfund, also of Berlin. In order to have the same density of grain in the measure, he used a funnel with a variable diameter nozzle, which was adjusted to suit the type of grain being tested. He also specified the distance between the funnel and the measure, and the time taken to fill lt.

Gniser noted that imperfections still arose because the weights were subjected to damage and wear, when they were dropped into the scale bucket, or when they were carried about by the grain merchants. But it was well over a century before further improvements were made, in 1912, when a 20 liter grain tester was admitted for verification in Berlin. This apparatus replaced the weight bucket with a hanger and slotted weights, and an improved method of filling was provided.

However, the 20 liter capacity proved to be too large for convenience, and after a few years, a 1/4 liter capacity was adopted. The cost of sending 1/4 L samples by post, was much cheaper for the merchants, hut it was much less accurate, so a 1 liter capacity also developed.

This system was used for some years, and then in 1937/38, the dimensions of each part of the tester, and especially of the capacity measure, were fixed. These specifications are still legal, and in use today.

Now to use a German Empire Grain tester

Now, a short description of the weighing procedure, mainly derived from the instructions given in the book of conversion tables:

"Amtliche Tafeln fur Getreideprobier mit Vorlaufkorper Bauarten bis 1937"

These tables show the weight of a Hectoliter (100 L) of grain against the measured weight of the sample.

The corn to be tested must be at room temperature, and air dried. During measurement the humidity must be between 50 and 75%. The grain tester, is set up on a strong horizontal table or bench, then the striking knife is inserted into the slot in the bucket. The suction cylinder is placed on top of the knife, and the filling pipe fixed to the top of the bucket.

The bulk density of the grain depends upon the quantity used, and how the filling pipe is filled. For this reason, the discharge cylinder must be filled only to the prescribed mark, and the use of a funnel is not permitted. The discharge cylinder is filled from the sack of grain, and then held 3 to 4 cm from the filling pipe. Grain is poured into the pipe steadily and to the middle, so that the grain will not touch the walls. The pouring time for a 1 L tester in about 12 seconds, and for a 1/4 L tester, about 8 seconds. (The discharge cylinder should be filled in the same time). 

Then the striking knife is pulled out quickly., without moving the bucket. The suction cylinder falls rapidly and creates a vacuum which causes the grain to follow and settle consistently, each time the tester is used. Holes are provided in the bottom of the bucket to release the air trapped below the cylinder.

At this stage, the striking knife is put beak into the slot, the excess grain is tipped out, and then the knife and filler pipe are removed. Now, the bucket is suspended from the scale and weighed to an accuracy of 0.5 gram.

Opposite the measured weight, in the conversion tables, the corresponding weight for a Hectoliter is found. Each type of grain has its optimum weight. If it is lighter or heavier than the Optimum, the utilization factor is poorer and the price is correspondingly lower.

 U. Schmidt (EQM Autumn 1978 )  










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