ELECTRIC OVEN HOT PROCESS

I work at home, and my office is next door to the kitchen, so using the oven for slow cooking comes naturally - that way I can keep an eye (or rather a nose) on what's going on while sitting at the computer.
So when I read about a crockpot experiment on the HotSoap list in the previous century, just as I was studying all I could find on HP and working up to taking the final plunge, I made a batch immediately and stuck it in the oven. HSD! No-hassle HP! 

That's a lot of HP batches ago, and it has mostly gone well. But unexpected things do happen. I've had:

* 1 Vesuvius: (That's when you get to clean soap off the roof of your oven) The soap started to crawl out of the pot while I was cleaning the stick blender. I stirred it down and stuck it in the oven, but a few minutes later the pot was an island in a sea of soap, thankfully contained in the oven. If you want to re-create the effect, you can mix your lye and oils at temps of 86 ºC, then get so fascinated by the patterns your stick blender are making that you blend to a VERY heavy trace. Nature does the rest; it's called an exothermal reaction, just in case you wanted to know.

* 5 Mauna Loas: a much more peaceful kind of volcano, when the soap stuff just crawls, almost apologetically, past the lid and snuggles down on the baking tray. 

* 1 geysir: I'd taken the pot out to stir, and when I stuck the spoon in, my goggles and the wall were splattered with flying soap. The lid hadn't been on properly, I guess, and a thick skin had formed on the surface of the soap. I've never had a repeat of the geysir effect, but now I stick my spoon in very carefully, and ask any spectators to step well back while I'm doing so.

I wondered at first if the Mauna Loas were caused by the oils I used for those two batches, but after deciphering my notes, I think the problem was caused by too high oven temperatures (95 ºC ), combined with too little soap in the pot (2 kg in a 9,5 -litre pot), so it got much too hot. 

I'm not sure if these things are the worst that can happen with oven slow cooking, but this is the worst that has happened to me, and it only entails some extra cleaning.

And the volcanoes aren't really that dramatic: I just opened the oven door, let them settle down a bit before I took out the pot, placed it on a newspaper, scraped the mess out of the oven with a spatula and put the pot back in and finished the cook, scrubbing out the oven later ... I even made a pizza in an unscrubbed oven once, in an emergency, and did not get "pizza á la sapone" ... but the fire alarm went off when I was pre-heating the oven.

The scrapings have since become liquid soap - I let them cure for a while, boiled them for a couple of hours on a slow heat with quite a lot of water, add orange essential oil and use it for washing floors.

There may be even more ways of cooking soap than there are of cooking rice, and I certainly don't think that my way of doing it is the final, definitive, one-and-only, perfect, never-to-be-deviated-from method ... I guess many of us get addicted to soaping partly because we love to experiment.

So instead of writing how-to instructions, I'm going to tell you what I do, and you can take it from there. With three exceptions:

* HEED ALL THE WARNINGS! Before you start doing anything, read the safety guidelines on soapmaking very carefully. There's no need to be hysterical about working with lye and boiling hot soap and so on, but it's important to respect the materials and chemical processes involved.
* KNOW YOUR OVEN: Can you set your thermostat at the temperatures recommended in cake recipes, or does your oven usually need lower or higher settings? Is it easy to clean? Are the oven trays lye-resistant? (Aluminum is not the thing here, even if you're not planning to make volcanoes). Does your oven have some sort of self-cleaning coating that might not appreciate lye?
* MAKE DETAILED NOTES ON EVERY BATCH. This is a case of "do as I say, not as I do". Or didn't. I really miss being able to look back and see exactly what temperatures I used, what amounts, which pot, what happened.

EQUIPMENT:
I have three stainless steel pots that fit in the oven - 9.5 litres, 6.5 litres and 15 litres.
I use very large and thick oven pads when I lift out the pot to stir it - it makes me feel more secure.
And I seem to use a lot of newspaper and kitchen tissue.
I'm allergic to rubber, so I can't use gloves, but if I do get lye on my hands, I just rinse well under cold running water.

 
METHODOLOGY:
Any kind of recipe can be used in OHP, but if you want to make soap with 100 % canola oil, don't put in in downspouts when it's done ... believe me on this; I really know what I'm talking about.

I always run my recipes through the MMS lye calculator, and use a bit more water than the recommended amount, just to make sure that the saponification is finished before the soap is cooked. I get some shrinkage when it's drying, but not much.
When I'm experimenting with a new recipe, I split a batch, take some out to  cure, and leave the rest in the pot to cook ... taking care that it is a bit less than half full, but not very much less, to put it scientifically.

Temperatures: I've tried to set the thermostat at different temps, from 70 ºC to (almost) 100 ºC, but have ended up with around 80 ºC (176 ºF) on my oven.
If I remember to, I turn on the oven when I've mixed the lye solution, that gives it time to heat up (this is a really old, slow oven). But the soap gets cooked even if the oven is turned on when I put in the pot - it just takes a bit longer.

The different stages of OHP are so similar to crockpot HP that I won't take up space describing them here - you can easily find info and pictures on the Web.
But it's important to keep in mind that the weirdest things can happen, but few are critical, and one usually ends up with some sort of soap: Once an OHP batch (coconut and soy shortening) decided to get stiff and unmanageable after 45 minutes, so I did something stupid - added a lot of water. And ended up with a thick and rubbery mess instead. In retrospect I think it would have been better to just continue cooking - or shove it into a mold (it was way beyond glopping), let it cure and rebatch it.

To stir or not to stir?
You don't have to, but then again, you don't not have to either. I'm always curious, so I usually take out the pot every 20 or 30 minutes and look and stir a bit ... and nothing awful has happened. And when I don't stir, nothing awful happens. But I always check once in a while to see if the soap is doing the volcano thing.

How long does it take?
That depends ... so I check every 20-30 minutes after the first hour, even if I'm not in a stirring mood. You can also turn off the heat and leave the soap in the oven overnight to continue saponifying, and then heat it up the next day until it is soft and pliable.

When is it done?
With some experience, you can smell when a soap is done cooking. You can also check by taking a small bit on a fork and placing it in a glass of hot water, stirring energetically. If it dissolves easily and foams easily, it's done. If it leaves a greasy slick on the surface, it needs some more cooking time. If it looks ok, take a bit more on your fork, let it cool and touch it with the tip of your tongue. If it doesn't sting, the pH is OK.

When you decide it's completely finished, it might be a good idea to leave it to rest for 30 minutes at around 40-50 degrees C before continuing - this seems to make it easier to handle when you're unmolding, and any essential or fragrance oils you'll be adding won't disappear in a cloud of steam.


SIMPLIFIED TRANSPARENT OHP:
To do this, you need Catherine Failor's book "Transparent Soapmaking". I use her recipes and follow her instructions. The only thing I do differently is to cook the soap in the electric oven (80C - 176F), and use a stick blender instead of a plastic tent.
Well - maybe I should explain the differences a bit more:
* Because the soap is cooked, it's not necessary to do the manual scraping thing that she recommends when the alcohol is added - I just scrape the sides and bottom with a rubber spatula. (In my oven, at this low temperature, the cooking time is more than three hours, but the soap turns out soft and very well-behaved)
* Failor's method calls for covering your pot with a "tent" of plastic sheeting to keep the alcohol from evaporating while it's being mixed into the soap, but I discovered that when I used the stick blender, that was not necessary - everything dissolved in a couple of minutes, long before any significant amount of alcohol could evaporate.
* Because everything happens so quickly, it's a good idea to make the sugar solution BEFORE adding the glycerin/alcohol.
* The batch is pretty big, but it can be remelted the next day. But pour it into large moulds instead of leaving it in the pot overnight - easier to cut up into smaller portions for remelting.
Happy soaping!