You might want to build thermocouples into the body of the oven. This is the high tech approach that a few of us have considered but I don't think anyone has actually gone for it. I costed it out at a few hundred quid (for I think 3 thermocouples and the gadget that they plug into), and decided I had other things to spend my money on
A pretty common approach is to fit a dial thermometer to the oven door, with a probe that extends back into the oven: this will allow you to check the temperature before and during bread baking and other door-on cooking, but that type of thermometer won't handle the kinds of temperatures you need for pizzas, not that you'd even have the door in place for that.
For pizzas, I think the simplest approach is to get a direct reading infrared digital pyrometer - they're readily available on eBay for about £20 or less, and will handle temps up to about 500°C or more.
Thermocouples have been used quite often in our (members) builds over the last few years. They are not so expensive and can be placed in the floor and the dome. I will try to find some archive stuff for you to use as reference.
......just in case ....if you go on our old forum, look through the categories AND also type in some keywords into the search facility (at top of page in blue letters)...forum link..
Like others, I considered using thermocouples but decided against it mainly based on cost, (its not just the relatively small cost of the tcs but the datalogger needed) as I think you probably need an array of 6-12 as a minimum. I doubt the usefulness of a single thermocouple, other than as a spot reading. If i was using a wfo commercially I would seriously consider thermocouple monitoring.
In respect of a commercial WFO, a major american manufacturer, Woodstone, use a single thermocouple based in the centre of the base stone. This is a replaceable item as shown on page 13 of this installation manual www.woodstone-corp.com/pdf/manuals/install_w.pdf
The thermocouple has been shown to be very reliable and repeatable. Excellent ovens used by restaurant chains Zizzi and Piccolino.
No reason not to install a thermocouple at home other than you need a power supply!
Many commerical chefs use a non-contact thermomometer such as a Raytemp 3 (500 degrees C) with laser spot. Much cheaper alternative to a thermocouple and found to be just as reliable.
The problem with only using a single TC is that it assumes that the whole of the oven space is the same temperature. This may be ok for a commercial wfo where the the oven is probably soaked with heat daily, but not for a domestic set up with intermittent firing.
My personal view is that if you are going to the trouble and cost of a TC setup you might as well do it right or not at all, particularly when there are cheap alternative methods of estimating temperature.
Totally agree with Tony. Even after 2 hours firing you can have a 300'C differential between top and bottom. I bought an IR laser pointer type thermometer for £12 and find it is more interesting than genuinely useful.
You could buy a few K type thermocouples and bury them in the mass. They are quite cheap but you need the high-temperature ones. These could be connected to a cheap multi-meter or a laptop.
The happiness of life is made up of minute fractions—the little soon-forgotten charities of a kiss, a smile, a kind look, a heartfelt compliment in the disguise of a playful raillery, and the countless other infinitessimals of pleasurable thought and genial feeling. – Samuel Taylor Coleridge
I deliberated about this for ages - not only will it be useful to see exactly how my oven performs, but I do like to geek out with tech
The cost of thermocouples and a reader initially put me off, and when I thought about it, I realised that one thing I am really enjoying about building my oven is that it's tech free - proper old school! I decided that (when it's complete) I'll do what I can to learn how my oven runs. If I do make one tech purchase, it will be an infra-red thermometer so that I can see how hot the oven gets.
I bought a couple of High temp Thermocouples (£4 each) from Hong-Kong at the end of last year and a dual input Digital Thermometer £20 incl p/p that shows both Temperatures, highest, lowest, average for each and the difference between the 2....
I've also looked into self build data logger (using ready made components) but these were limited to fairly small temperature ranges... I'll look into this again when the raspberry pi finally turns up ;-)
I'll be retro-fitting my clay oven in the coming months, just got to find a drill bit long enough to get through all that clay.... as for the floor, I never stuck the bricks down, and although they are currently looking very neat on settled, I might pull them all out and refit on top of something more insulating than the bricks and sand I used underneath originally... if I do, I'll put a couple of k-types in the floor too..
This is all just for geeky nerdyness though... after you have used a wood oven a few times, you just know when it is hot enough ;-) but it was interesting to see the the temp edging towards 800C during the Bonfirenight firing....