Need cooking advice? Good Food guru Richard Cornish attempts to answer your vexing culinary problems each week.

A friend's son wants to become a chef but he doesn't have any tatts. Is it possible to become a credible chef without any tattoos? - T. John

I posed this conundrum to scores of top chefs across the world asking them if they had any tattoos. Only a handful answered my request. According to Massimo Bottura, the chef at Osteria Francescana, currently the No. 1 rated restaurant on the planet according to The World's 50 Best Restaurant list, he recently gave himself a tattoo that reads "no excuses". Martin Benn from Sepia does not have any dermography nor do any of the top chefs he has worked with recently. Neither Guy Grossi or Stefano Di Pieri are inked nor is Michael Ryan from Provenance in Beechworth or Dan Hunter from Brae. Prolific Melbourne chef and restaurateur Andrew McConnell has a Chinese triad-style dragon needled into his lower leg but his alumnus Matt Wilkinson claims to have been too poor to get a tatt when he was young and foolish. The common thread tying these chefs together is their commitment to hard work, understanding and application of technique, ability to communicate to staff and customers, a creative attitude to what life throws at them and a real sense of hospitality. Compared with these, tattoos are simply garnish. 

The real deal: Vanilla extract comes from vanilla beans; vanilla essence does not.

What is the difference between vanilla essence and vanilla extract? - L. Harrison

In general, vanilla essence is made with a man-made compound while vanilla extract comes from vanilla beans. Common to both is an arrangement of carbon, hydrogen and oxygen atoms that give us that warm, fruity and appetising olfactory sensation. Called vanillin, it is naturally occurring in oak – imparting a vanilla characteristic to wines stored in oak barrels, as well as "fruity" olive oils and some tropical fruits such as lychee. It can form spontaneously when food is heated causing the vanilla aroma in coffee beans. Vanillin was synthesised from pine bark in 1874 by German scientists Tiemann and Haarmann. Today, it is mainly made from waste from the cellulose industry. To confuse matters, some brands of vanilla essence, such as Queens, however, are made with natural extract. Read the ingredients list.     

It's called botulism. It's like Botox except your face doesn't move – ever again. As well as your heart and lungs. Botulism is the often fatal, but fortunately not that common, poisoning caused after eating food contaminated with toxin created by the bug Clostridium botulinum. It thrives in anaerobic, or air free, conditions such as raw food stored under oil. It is possible to store food under oil if the food is under pH of 4.6 which is very strongly acidic. Alternatively look up recipes for sott'olio, an Italian method for preserving under oil in which vegetables are dried and salted, covered in oil and pasteurised. Best not to poison people at Christmas, no matter how much you feel like it.