# Potato with core temperature of 100C but no carbonisation

I was experimenting to find out that is the temperature at which a potato is "baked", i.e. edible and completely cooked but not burned.

I put one in a tiny pot in my oven at 100C, thinking it won't actually reach 100C and left it for many hours.

When I eventually pulled it out I took a candy thermometer and checked its core temperature and it was, indeed 100 degrees Celsius. Yet the potato was fine, it was not even slightly burned and no part of it has been turned to charcoal. It was a peeled potato.

As far as I know at 80 degrees tissues start turning to charcoal so I am completely flabbergasted as to how this is possible.

• Where did you get the idea that tissues turn to charcoal at 80 degrees? And why would you expect potatoes to act like tissues? Commented Jul 19, 2022 at 0:55

There are many issues with your assumptions, settings, and procedures. I'll point a couple out:

1. 100C is a very low oven temperature...not a problem, but it will lengthen the cooking time.
2. Ovens are notoriously inaccurate. The temperate inside your oven was likely not 100C and could have been much lower (or even higher), but you didn't measure it, so you don't know.
3. A potato is fully baked when it reaches about 100C at the core. So, with your oven set at that temperature, I would guess it would take several hours to get the internal temperature of a potato to that point.
4. If your reporting of the internal temperature is accurate, you baked it perfectly, so it would not burn or caramelize.
5. Potatoes are quite moist, and evaporative cooling keeps the surface temperature well below your oven temperature, not a situation where caramelization would happen.
6. Paper will not ignite until somewhere in the 225C and above range, but that varies depending on thickness and moisture content.

Given all of this, your results are not surprising. It would probably take a few hours to bake a potato in a 100 C oven. Now that you know a potato is "baked" when the internal temperature is about 100C, you can save yourself some time by setting your oven at a higher temperature.

• Note that it's possible to "bake" potatoes in a slow cooker, and even on high that barely exceeds boiling Commented Jul 19, 2022 at 7:13
• You could also start at say 120C then reduce to 100, or put a thick metal skewer through the potato. Aluminium ones and even 4-pronged frames were sold for this purpose Commented Jul 19, 2022 at 7:15
• @ChrisH, for your second point, I assume you are providing a tip for faster cooking (as the skewer conducts heat through the center of the potato.) As a side note for the OP, I usually bake potatoes at 190-200C (skins on) for about an hour...no skewer). Commented Jul 19, 2022 at 10:14
• Yes, sorry, hastily posted as I finished breakfast. You're exactly right. The thermal conductivity of potato is pretty low, so a thick aluminium skewer provides a shortcut for heat to reach the middle and reduce the hours it would take to cook at low temperatures. I normally use my combination microwave, with enough oven heat to cook the skin, but accelerated with microwaving. That takes about 20 minutes. I only use the oven for jacket potatoes if I'm heating it up for something else. Commented Jul 19, 2022 at 10:19

The potato (a wet thing) was in a pot (contains steam, if covered. Unclear if you covered the pot or not, but the fact that you mention a pot implies a cover, as opposed to a baking tray/pan/sheet.) With a cover, the potato would be essentially oven-steamed. Without a cover, baked at very low temperature.

Nothing carbonizes at 80 °C - certainly not potatoes. Some things become unpleasant to eat if cooked that hot, but they don't carbonize. Time to unlearn some incorrect knowledge by the power of actual experiment. Flabbergast whoever taught you that, it was in error.

Typical baking temperatures for potatoes (or "oven fries" if looking for "without skin" information) are MUCH higher, and the potatoes do not turn to charcoal, even a little bit, unless ignored for an excessively long time. 200 °C on the lower end of typical (at a longer time) for skin-on whole potatoes, 230 °C on the higher end of typical and when attempting to achieve "fried" with an oven (where heat transfer is rather slow compared to oil.)

Deep-fried (in oil) potatoes are typically fried (which transfers heat much more quickly to the surface layers) at 185-190 °C. More usually first at a lower temperature, rested, then finished at that temperature. They will burn if ignored too long on a much shorter timescale.