Sunday, 24 August 2014

Kitchen Gadget 8. Thermometer

Being scientists at heart we love lots of gadgets that make cooking more predictable, and this is definitely one of them. The food thermometer. Again, a very simple piece of kit, we bought ours from ebay for the princely sum of £3 and it gets used several times a week, though often this is as an upgrade to the little finger method of testing our reheated dinner is hot enough. It's been called in to service for everything from sugar syrups and caramels to checking BBQ food is safe and meats are cooked to perfection.

As an aside; when we're on our own we tend to cook enough for four people and eat the same thing for two nights. An odd habit but we've found it tends to be a little cheaper and means we only cook from scratch every other day - we both work full time and as much as we love cooking we also like getting home and not having to cook. Popping something in the oven to warm up is therefore an everyday occurrence (no microwave - about the only gadget we don't own).

Back to the topic at hand; on occasion we use our thermometer for slightly more technical things than reheats. This week we had roast pork and did just that.

Roasting with a Thermometer

Temperature has a very predictable effect on meat, be it a joint, fillet, or whole bird and you can use this knowledge to aid you in your cooking. Knowing the temperature of the centre of your meat will tell you all you need to know about its current state and should mean that you can go through the whole cooking process without needing to cut it open and check the colour.

The same temperatures apply to all meats - though what is considered a safe temperature varies. There are many references to what each temperature means for the proteins in the meat you are cooking, and we won't attempt to match that level of detail here - instead, we've put together a quick guide to the temperatures we refer to most.

McGee on Food and Cooking by Harold McGee has plenty to say on the subject!


How well done is my red meat?
55C - Medium Rare
60C - Medium
70C - Well Done
90C - Falling apart
Don't forget that these are the maximum temperatures in the middle - a big roast will climb a few degrees whilst resting (up to 10 for a particularly large joint) so if you want your roast beef perfectly cooked pull it out a few degrees early.

What's safe for other meats?
60-70C will kill most bacteria depending on how long the meat is held at that temperature, but over 65 is a safe bet. You also need to make sure you are measuring the thickest part of the meat - the outer section will be much hotter but it is the minimum temperature in the meat that matters. 90C in the middle will have it falling to pieces so long as it is still moist - 90C and baked dry will be like leather!

What does the Food Standards Agency have to say about this?
If we have any doubt about the quality of the meat we always go for food standards agency levels. Sausages, regular burgers, reheating things that have been in the fridge too long etc all get this treatment. I'm sure many chefs would point out that the best ways of cooking things wouldn't always hit these guidelines though! They recommend achieving one of 60C for 45 mins, 65C for 10 mins, 70C for 2 mins, 75C for 30secs or 80C for 6s.

We work on the 80C and it's dead rule - gives a bit of leeway for error of temperature reading. It is also a great target for most BBQ foods - its surprising how paranoid we have become about burning our sausages and chicken to a crisp before declaring it cooked but a quick stabbing with the temperature probe can ensure the food comes off cooked but still juicy and tender.


Roast Pork

The joint was seasoned and sat in an oven at 180C. After around 45mins it registered 49C, not cooked yet.

40mins later it had reached 72C. This is now cooked and safe to eat but not quite what we were aiming for on this occasion.

Finally we reached 88C - plenty enough to clear 90C after resting. This joint could bake to falling apart temperature as it had a good layer of fat on it to keep it moist.  After being covered in foil for 15 mins it was ready for carving. Being only a small joint 15 minutes was plenty of resting time and allowed it to rise the last couple of degrees. We tend to leave big joints 20-30 minutes to rest.

Perfect.



2 comments:

  1. Your gadgets are beginning to appear on my Christmas list!xxx

    ReplyDelete

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