The turkey is, for many people, the centrepiece of Christmas. This bird represents the largesse of the season, the over-importance of festive food. Its very existence is associated with the Christmas season (how many other times a year do you eat turkey? We’re betting not many). Yet the word turkey means stupidity or ineptitude. Put bluntly, you’ll feel like a real turkey if you don’t cook the turkey just right.
The full pressure of Christmas is placed upon the chubby, fragile shoulders of this bird. It forms the crux of the traditional Christmas dinner – and if it turns out poorly, the day could turn as dry and sawdusty as the overcooked bird. Add in one too many sherries and disagreeable relatives and the fragile Christmas spirit you’ve amassed will fall down around your ears.
By some cruel twist of fate, the turkey is a tricky bird to cook. Its large size means it’s all too easy to overdo it, turning the meat dry and chewy. Salmonella from undercooked meat is even more undesirable. So what’s a stressed host to do? Should we give up on Christmas altogether and run for the hills?
Luckily for this overdramatic writer, there is a ready balm for these wounds and it’s not comprised of butter, bacon or anything else you might try to moisten a dry turkey breast with.
Dr Peter Barham, a physicist from the University of Bristol who has worked with chefs and contributed to the invention of molecular gastronomy, brings a scientist’s perspective to the Christmas table. He spoke to PhysOrg about the scientific approach to cooking a turkey.
It all comes down to temperature. As a turkey cooks, its protein molecules start to denature, which makes them coil up and become smaller. This causes the muscles of the bird to contract. Parts of the turkey are rich in collagen, which only becomes tender and digestible at around 60°C (140°F). So the bird must reach those slightly higher temperatures to render the collagen-rich wings and legs edible and tasty.
The United States Department of Agriculture recommends cooking a turkey to at least 74°C (165°F), so that’s what you should aim for.
Dr Barham says: ‘The longer you cook any meat the “tougher” the muscle fibres will become.’
Don’t cook your turkey for too long at a high temperature. Easy enough. There’s more, however.
Dr Barham continues: ‘A turkey is around 60% water. Most of the water in a piece of meat remains bound to the proteins. When proteins are denatured some of this bound water can escape. You can see this when you fry meat: after a short cooking time, some liquid (mostly water) will start to flow out of the meat and as it boils in the hot fat it “spits” at you. If significant amounts of water are lost in this way the cooked meat will seem dry.’
You can avoid this by avoiding cutting into your meat while it’s cooking, to keep as much water inside as possible, by using a meat thermometer to check to internal temperature and again, by not cooking it at too high a temperature for too long.
To ensure that your turkey is not only tender and juicy but also flavourful is a trick rather than a complicated technique.
Dr Barham says: ‘By far the largest component of flavour is the aroma (detected in the nose), rather than the taste (detected in the mouth), so flavour is dominated by small volatile molecules. Cooking produces many of these, and the ones we recognise as having “meaty” aromas are generated through a series of reactions between proteins and sugars known collectively as the Maillard reactions.
‘The reactions that generate the cooked turkey flavour only really start at a respectable rate above about 140°C (284°F), but if the temperature exceeds 200°C (392°F) then different reactions leading to bitter and even carcinogenic compounds can set in.’
Thus, here is how to cook a perfect turkey, as put together by Dr Barham: ‘The outside needs to be heated to between 140 and 200°C (284 and 392°F) to make sure the Maillard reactions provide plenty of the “turkey” flavour.’
This needs to be combined with not overcooking the breast meat while still ensuring the legs cook enough for the collagen to break down and become tender.
So how do you actually achieve this? By far the easiest way is to have the turkey jointed so you can cook different parts of the bird at different temperatures, for example cooking the legs first, then adding the breast later in the cooking process so it doesn’t become tough. If you want to serve the impressively traditional whole turkey at the table, however, this isn’t possible.
Dr Barham has the solution. He says: ‘My own favoured cooking method is to cover the more delicate breasts with aluminium foil to keep them from getting too hot as the wings and legs cook and only remove this foil towards the end of the cooking. To reduce the evaporation of water and to improve heat transfer I cook in a moist oven, by keeping stock under the turkey as it cooks. Use a probe to measure the temperature inside the different parts of the bird so that you can control when to take off the foil and when to take the turkey out of the oven.’
So there we are. To cook a perfect turkey and avoid a Christmas catastrophe, all you need is some aluminium foil, a tray of stock, a meat thermometer and a tiny bit of diligence.
Go forth and cook, my little turkeys. You can do it!
The secret to cooking a perfect turkey: