Objective
To produce a substitute for malted or steam flaked barley in brewing, that would use less energy and give an acceptable extract level. For the first time in a brewery, Maltomat Milled Barley is to be produced with an extract level of c. 90% of that of malted barley using less than 20% of the energy required for conventional malted barley.
This project is to replace in future 23% of the malted barley used in brewing with Maltomat Milled Barley, showing an energy saving of 1878 TOE/Annum.
The installation first entered full service from the 7th April 1997 and since that date has suffered no prolonged stoppages apart from a 14 day period where it was necessary to run down the torrified barley stock which had been purchased for use following the delay between the closure of the flaking plant and the commencement of the Maltomat milling of barley.
The measurement and monitoring period was taken over the initial six monthly period up until 5th October 1997. During this period, Maltomat milled barley was used to produce a range of Guinness products including Irish Draught Stout (IDS) at a grist ratio of 1 part milled barley to 3 parts malted barley.
The data relating to the milled barley throughput and electrical power consumption was collected on weekly report sheets. The total milled barley over the 26 week period was 4853.26 tonnes. The average electrical power consumption during the period was downwards from a high of 6223 kWhs/ tonne during the second week of monitoring to 5115 kWhs/tonne at week 29 (15th week of monitoring)
Based on the projected annual throuhput of 15000 tonnes, the actual quantity during the monitoring phase of the project was 35% low. This was due to :
- 14 days production when stocks of torrefied barley were processed (8%)
- Rationalisation of the brewery product mix over recent years.
- Seasonality variations.
The budgeted annual throughput of barley for 1997/98 is 13200 tonnes; this is only a 12% reduction when compared to the original projected figure of 1992.
The actual kieve turnaround time has been maintained with production throughputs unchanged when compared to all malt brews.The finger printing tests for roller wear have indicated a wear rate of 10% over the monitoring period. This is inline with what was expected for replacement every 2-3 years.
The malting process is energy intensive and during periods when unit costs for energy have risen steeply or when there has been a substantial shortfall in energy, the price/supply problems have encouraged the brewer to consider the use of unmalted cereals.
The ease with which extract can be recovered from the different forms of barley adjunct depends on the extent of disruption and gelatinisation which occurs during their preparation. Gelatinisation is usually defined as the rupturing of the starch cells.
Of the unmalted cereals, the Maltomat Milled Barley on technical grounds has much in its favour when compared with raw barley, steam flaked barley and torrified barley in terms of extract recovery. The Maltomat Milling process involves the weighing and feeding of raw barley into a 6 roller configuration machine. The first set of rollers is used to pre-crush the kernals with the second set stripping any adhering starchy endosperm particles from the husk.
Following this operation of stripping, a new sieving arrangement has been incorporated to essentially only allow the starchy endosperms to go forward to the final pair of rollers. The final set specifically mills the endosperm (GRITS) fractions.
The whole process incorporates the optimum three stages necessary for the preparation of high extract levels for untreated barley. Innovatory features include :
* Automatic gap setting for 6 roller configuration
* Differential roller speeds
* Fluting of the rollers
* Feed rate control
* Sieving
* Materials of construction
Malted barley requires 0.151 TOE/tonne to process, while the Maltomat Milling Process should only need 0.0104 TOE/tonne* (* It is what was expected as specific energy consumption of the Maltomat Milling process at the beginning of the project (i.e. at the time of the contract). However, according to the results obtained at the monitoring phase, the specific energy consumption of the Maltomat Milling Process is approxim. 0.0066 TOE/tonne)
Programme(s)
Topic(s)
Call for proposal
Data not availableFunding Scheme
DEM - Demonstration contractsCoordinator
8 Dublin
Ireland