Why is some balsamic vinegar so expensive?

Why is some balsamic vinegar so expensive? The glaze costs under $5 in the supermarkets but some bottles are $30. M. Glover

I'll ask you a question first. Why are Mercedes so expensive when I can buy a Hyundai for under $25,000? Traditional balsamic vinegar, Aceto Balsamico de Modena, is made in the Italian region of Emilia-Romagna from grape juice that is boiled to make a thick dark must.

During this cooking process some of the sugars are caramelised to create a dark colour and react with amino acids to create rich flavours. Food geeks will recognise this as the Maillard reaction that makes cooked meat so delicious. This must, or mosto, is aged in different types of wooden barrels where an unusual yeast that can survive in very sweet and acidic conditions turns the sugar into alcohol, which in turn becomes acetic acid: vinegar. The wood barrels are porous and the balsamic reduces about 10 per cent each year and is topped up with vinegar from younger barrels.

The final product must have an average age of 12 years. Some are aged much longer, the resulting balsamic vinegar being 100 times the concentration of the original grape juice from which it was made. Balsamic glaze is often a mix of vacuum-reduced grape juice, vinegar and caramel colouring. It's sweet and sour and can be quite tasty. But it is in no way as complex or interesting as the real deal.

Why do fish smell? V. Micelli

I am a latecomer to fishing. Having kids means passing on obligatory survival skills. Fishing teaches about baiting up, casting off and, most importantly, disappointment. The elation of catching a fish to feed the family is palpable. There are enzymes in fish that break down the unsaturated oils in the flesh compounds that have a ''green'' grassy smell.

The aroma of the sea comes from algae that create compounds from the element bromine in seawater. Fish eat the algae or eat other fish that eat the algae. ''Fishiness'' comes from a compound called TMA, formed when bacteria break down another compound, trimethyline oxide, which stops saltwater from drying out the fish. TMA in turn breaks down into a compound that smells like ammonia.

Sharks and stingrays have urea in their bodies that actually turns into ammonia. Fishing teaches kids about smells, particularly when someone forgets to take the bait sandworm out their pocket and leaves their shorts under their bed.

What is so special about padron peppers? N. Petrie

Pimientos de Padron refers to little green peppers from a region of Galicia in Spain around a town called Padron. It is said they were cultivated from the original peppers introduced from Mexico by monks after the invasion of the conquistadors.

They have a lovely clean flavour, like a slightly sweet and intense green capsicum. In Spain they are generally deep-fried or grilled and served in a small bowl as a snack. What is special is that, quite randomly, about one in a dozen is hot. This changes depending on the conditions of the season.

Generally Spaniards do not like spicy food, but some enjoy watching a person in a bar hit a spicy pimiento de padron and react dramatically. You can buy them here in speciality greengrocers or via the web at midyimeco.com.au.

Menu howlers

Your response to and interest in the amusing mistakes on restaurant menus has been overwhelming - and somewhat disturbing. Take the Blue Mountains restaurant that, without irony, was serving ''Veal Gordon Blue''. Thank you D. Ruston. Or the Carnegie restaurant, according to L. Daglish, that apparently served ''Japanese Nudes''. A now-closed restaurant in Dandenong was serving a ''3 coarse meal''. E. Reeders read on a menu in a country cafe, ''For glutton-free options see waiter''. Perhaps the favourite of the week has been from B. Yuncken who, while dining on a Russian train, was perplexed to see this on the bottom of the menu. ''We are unable to take credit card. We hope that this does not cause incontinence.'' Thank you everyone.

Send your queries to brainfood@richardcornish.com.au