Dry ageing sheep meat for a premium product
Robin Jacob, DPIRD, WA and Melindee Hastie, University of Melbourne, VIC
Author correspondence: robin.jacob@dpird.wa.gov.au
The interest in dry ageing is growing in countries like the USA and Germany, particularly amongst the “foodie” segment of consumers. In the USA for example, the dry aged beef industry has grown from virtually nothing in 2011 to a $10 billion industry, and is equivalent to about 10% of their beef industry. Described by some as the “the chocolate” of meat dishes, the potential is to add value to meat using this traditional method of ageing, where meat is aged under controlled temperature and humidity conditions for weeks or even months.
The process causes tenderisation, the degree to which is dependent of the length of time the meat is aged for after slaughter. Dry ageing potentially also causes the flavour profile to change and intensify. This flavour tends to be rich and ‘buttery’, hence the comparison made by foodies to chocolate. These eating quality factors together can increase the price consumers are willing to pay for meat.
The DPIRD’s Sheep Industry Business Innovation project (SIBI) teamed up with MLA to investigate the possibility of value adding to mutton using dry aging. The project, conducted by the University of Melbourne, included measurements of moisture loss and a Meat Standards Australia (MSA) style consumer sensory panel assessment.
Materials and methods
In this experiment, carcases from 90 cull for age Merino ewes (animal age ranging from 3 to 8 years with an average of 5 years), were aged for 14, 28, 42 or 56 days. For comparison, half of each carcase was wet aged in contemporary vacuum bags and the other half was dry aged using a purpose built dry ageing facility. Dry ageing conditions were tightly controlled with a cabinet temperature range of 0-1.0ºC, relative humidity maintained at 80-85%, and auxiliary fans providing continuous air movement within the cabinet.
Results and discussion
Figure 5 shows preliminary results for weight loss from wet and dry aged legs. The difference in weight loss between ageing treatments is quite dramatic. Regardless of the length of ageing, wet aged legs lost less than 1.7% moisture.
In the dry aged legs, moisture loss was 11.5% after 14 days and increased over time, peaking at 20.6% after 56 days. The difference between moisture loss in dry and wet aged legs was statistically significant for all ageing periods.
Ageing for extended periods to achieve tenderisation and flavour effects caused weight loss that increased with time. Quantifying the weight lost in this way allows for a better understanding of the cost of the process, because weight loss reduces the amount available for sale compared to wet ageing.
Justifying the cost of any weight loss with a price increase, in dollars per kilogram, will depend on the associated flavour and tenderness attributes. A future edition of Ovine Observer will report the consumer assessment results, comparing the tenderness, juiciness and flavour of wet and dry aged sheep meat.