How to crimp

In order to produce Crimped Grain of the highest quality every time, make sure that you follow these 10 Golden Rules:

1. Ensure that all areas where the grain is to be handled and stored are clean. Grain handling machinery must also be thoroughly cleaned before use.

2. Treat storage areas prior to harvest to eliminate grain-storage pests such as grain mites, weevils and grain beetles. If possible avoid storing straw close to crimped grain – infestation by grain-storage pests can be transmitted from straw.

3. Check grain moisture content and use CrimpSafe 300 or CrimpSafe Hi-Dry Preservative at the recommended rate for the tested grain moisture – application rates are shown in the tables at the end of this brochure. Contact your Kelvin Cave Ltd representative for advice on checking moisture content correctly. N.B. Normal moisture meters will not give accurate readings above 30% moisture. However, Kelvin Cave can supply an easy to use, specially calibrated moisture meter that will give accurate readings up to 50% moisture.

4. Process and ensile all grain within 24 hours of harvesting.

5. Ensure the Murska or Korte crimper is set correctly so that all grains are crushed. Calibrate the preservative applicator to apply the recommended amount of CrimpSafe. The crimper should be fitted with spray nozzles to ensure even coverage with CrimpSafe as the grain travels along the bottom auger.

6. Make sure that the clamp walls are solid and can withstand the pressure of consolidation.

7. Consolidate the crimped crop well, in thin layers, using the Dorset Wedge method.

8. Keep the clamp sealed for at least three weeks before feeding. Make sure that all air is excluded. Use new, heavy-duty polythene side-sheeting and cover the clamp with O2 Barrier 2in1 top sheet for the most effective air-tight seal. Alternatively, use ClampFilm™ vacuum-film covered with a good-quality 125µm top-sheet. All covering should be weighted-down evenly, ClampTiles from Kelvin Cave Ltd are ideal for this job providing even weight and protection from bird damage.

9. Cut the feed neatly from the face and manage it so that feed is removed across the whole face at least once a week, or more frequently in warmer weather. Keep the face of the clamp uncovered, pulling the sheet down over an open face can create an ‘incubator for spoilage organisms.

10. Take precautions against vermin. Rats, mice and birds can cause damage to your crimped grain; your local Kelvin Cave representative can give you useful advice on how to avoid this.

When to crimp

All cereal crops (wheat, triticale, barley and oats) are at their optimal nutrient value and digestibility when their natural moisture content is between 35 and 45% moisture. This stage is reached when the stem immediately below the ear has turned yellow in the majority of plants. Grain from the middle of the ear should be at the ‘firm cheese’ stage, and can be squashed between thumb and finger with no visible moisture squeezing out. As moisture content decreases the digestibility of the grain reduces. CrimpSafe 300 is the appropriate preservative to use on grain from 25-45% moisture. (See table for correct application rates).

Once the grain moisture falls below 25% there is insufficient moisture to allow a fermentation to take place and it becomes more difficult to remove all air from the grain mass in the silo. Once this point is reached CrimpSafe Hi-Dry should be used to ensure effective preservation.

Peas and Lupins should be harvested at 25-30% moisture. The plants will have died and the pulses should be firm but ‘chewy’ rather than ‘crunchy’.  Again CrimpSafe 300 is the appropriate preservative to use at the recommended application rate. CrimpSafe Hi-Dry should be used below 25% moisture.

Beans should be harvested below 25% moisture and can be ensiled when treated with Propcorn NC at 9 litres/tonne.

Maize grain should also be harvested as near to 30% moisture as possible. The plants should have lost their green colour at this stage. Remove the cob from its sheath and grip it firmly in both hands. If it produces a slight rattling sound when rotating the hands in opposite directions, it is ready to harvest. In the UK it is rare for maize grain moisture content to drop below 30% in the standing crop. In order to produce crimped maize and other crimped grain of the highest quality every time, make sure that you follow these 10 Golden Rules:


Generally speaking, combining crops for crimping is no more difficult than combining traditionally. Remember that when the crop is harvested at the earlier high-moisture stage it will be bulkier than when it has dried out completely so it may be necessary to drive the combine harvester a little slower. Provided the crop is not wet with external moisture it should present no significant problems. Your Kelvin Cave representative can give useful advice on refining combine settings to optimise performance. Andy Strzelecki our Technical Director was invited by EBLEX to record some guidance videos demonstrating the ideal stages to harvest cereal crops for wholecrop and crimping and these can be viewed here.


Crimped grain can be stored in a conventional clamp or silo, or a special plastic-tube bag filled by a Korte crimper/bagger.

Before harvesting prepare the clamp or bagging site. All areas that will come into contact with the grain should be thoroughly cleaned, as should vehicles that will be used for grain handling and clamp consolidation. Clamp walls should be lined with heavy-duty side-sheeting. 1 tonne of consolidated crimped grain will occupy approximately 1 cubic metre.

Crimp through the Murska or Korte crimper, adding the appropriate CrimpSafe preservative at the recommended rate, and ensile within 24 hours of combining. Fill the clamp in thin layers using the Dorset Wedge method and rolling well to remove all air. If the top surface dries out during a break while filling, damp the dried surface with CrimpSafe from a watering can fitted with a fine rose before adding fresh material.

When all the grain has been processed and properly consolidated in the clamp, damp the surface again with CrimpSafe and cover immediately with O2 Barrier 2in1 top sheet. Fold the side sheets over it and weight down to exclude all air. Pay particular attention to the seal between the plastic and the concrete at the bottom of the ramp, loose sand, soil or gravel bags are the most effective weights at this point, creating a perfect seal between the sheet and the concrete.

Grain Crimpers & Dry Grain Roller Mills

Grain Crimpers & Dry Grain Roller Mills

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