Walnuts are imported into Australia mainly from California (USA) and China. The Australian walnut crop is growing – so you will find some walnuts from Tasmania, Victoria and parts of NSW and South Australia.
If you're buying them in the shell, look for ones that are heavy for their size, and with intact shells. Shelled walnuts should be plump and crisp. If they're packaged, look for airtight packaging and buy the ones with the longest time remaining on the best-before date.
Store walnuts in an airtight container in the refrigerator or freezer. They should keep in the fridge for 4 months (and 6 in the freezer).
Walnuts that have been stored for too long go rancid – which makes them bitter.
Getting your walnut out of its shell without breaking the two nut kernels inside is something of an art. A nutcracker works, but not everyone has one, and it can do a lot of damage to the nut kernels.
According to the Australian Walnut Industry Association all you need is a teaspoon: put the handle end in the depression where the walnut was attached to its stem and twist.
Walnuts are rich in omega-3 fats – a 30 gram handful of walnuts has 1800 mg of omega-3s.
There are two types of omega-3 fats – the kind found in plants (including walnuts) and the kind found in oily fish. Plant omega-3s are important in heart health.
Please note: this information was current as of February 2007 but is still a useful guide today.