Grains Research and Development

Date: 01.03.2001

Does your storage turn malt grade to feed? by Denys Slee

Silos

It's one thing to produce malting grade barley in the paddock; it's quite another to keep it as malting grade in storage.

GRDC Program Consultant Deirdre Davis says, "there is industry concern about the loss of germination in malting barley in storage and the grain being downgraded to lower-priced feed quality".

That answer may flow from research at the CSIRO Stored Grain Research Laboratory (SGRL), particularly on in-storage cooling and aeration-drying. Scientist Len Caddick says maltsters generally require malting barley to have a minimum 96 per cent germination level.

But that vigour faces many potential pitfalls: field conditions at harvest such as temperature, rainfall and humidity, and the harvesting process itself if the grain is physically damaged.

"As well, the barley can lose germination if it is stored at high temperatures and high moisture levels," Mr Caddick said.

"A lot of our barley is harvested in temperatures above 30°C but our research has shown that if you can reduce the temperature of sound malting barley to the low 20s and keep it there, you should be able to maintain malting grade for up to 12 months."

Mr Caddick said cooling of newly harvested grain was a key to maintaining malting quality while aeration-drying of high moisture level grain (often harvested early) was a complementary development that reduces risk.

Trend for higher moisture receivals

Ms Davis said a significant trend for barley moisture receival levels around Australia was the change from the traditional 12.0-12.5 per cent range. SA had for some time received barley at the higher maximum moisture level of 13.5 per cent and now WA too was taking malting barley into aerated storages at 13.5 per cent at selected sites.

"There is potential to minimise harvesting delays as well as to reduce the risk of downgrading caused by weather damage," she said.

Lesley MacLeod of Barrett Burston said the SGRL research was of great significance.

"For our industry the grain is a living thing and it has to be alive when we get it so that it can be germinated. In the research, cool temperatures and low moisture levels during storage produced superior malt quality compared to malt made from grain stored at higher moisture levels and at high temperatures."

What's it cost?

On-farm, the capital cost of an aeration facility for a 50-tonne silo including ducting and a controller is about $2,000 but would be higher if a high drying air-flow rate was required. Operational costs are low, 50c/t or less for cooling and $10/t or less for drying — the latter cost depending on how much drying needs to be done. Insect activity is also better suppressed with aeration.

Mr Caddick said that CSIRO and grain industry storage interests were developing a new aeration control program to facilitate better grain temperature and moisture management on farm. This should be available in about 18 months.

Program 1.8.1 Contact: Ms Deirdre Davis 02 9882 2227 Dr Len Caddick 02 6246 4214