Category Archives: Experiments

Re-visiting and seasoning the Holcroft skillet

Over the winter of 2015-16 I tried out a new method for restoring a very rusty cast iron old Holcroft skillet that had been used as a garden ornament for many years and was decidedly the worse for wear. I recently came across a picture I’d taken of it in 2006 and it had been a garden ornament for a good while then. There were nearly ten more years of rusting after that!

In its original spot

Anyway, a bit of back story. We work in woodland over the winter (more on that here) and a hot lunch is extremely welcome, so we decided to start making proper use of the skillet. Some logs and slabs of stone had been used to form sitting places and were already nicely set out to be used as an outdoor cooking area, so that’s where we cook.

The kitchen

Come lunchtime, we bring out the basket of supplies, set up the stove and get cooking.

This stove is an MSR Dragonfly multi-fuel stove and while it isn’t cheap, it’s a well made piece of kit and runs on any petroleum-based fuel. The first time we cooked bacon and egg rolls was delightful – just the two of us in the middle of the woods on a chilly January day and we could provide ourselves with a hot meal. We’ve cooked for other people since that first time and everyone has reacted with the same pleasure. It’s an instant mood-lifter.

I had previously seasoned the skillet using lard and it worked pretty well – the first eggs cooked in it came out perfectly and nothing stuck to the pan. We used it all winter with no issues. At home, I’d scrub it out with a hard brush and hot water, dry it straight away and wipe a light coating of oil or fat over it to keep the rust off.

The thing is, if it wasn’t wiped with oil or was left wet, then it did rust, so I looked for other seasoning methods and came across Sheryl Canter’s excellent blog on the chemistry of cast iron seasoning. Here, she discusses the polymerisation qualities of varying oils and fats and explains why flax oil is the best to use for seasoning. Polymerisation means that the combination of iron, heat, oil and oxygen creates a plastic-like protective layer on the iron. She recommends that you use the oven’s self-cleaning function to clean off old seasoning, but our oven doesn’t have that feature so I just scrubbed it out as well as I could.

The idea goes like this: put the pan in the oven and heat to 100C to open up the iron’s pores. Take the pan out and wipe all the inside surfaces with the lightest smear of flax oil (you must use pure food-grade flax oil), then wipe it again to make sure you’ve removed any excess. Put it back in the oven, turn to full heat and let the pan bake for an hour. Turn the oven off and let the pan cool completely. Repeat five or six times until you have a smooth dark veneer on the pan’s cooking surface.

Without having the inside ground by a machine, a smooth veneer simply isn’t going to happen with that old skillet, but I thought it could do with some TLC, so decided to give the method a go. Five seasonings later and it’s looking pretty good, even wood-ready. Compared to how it was before I started work on it, it’s impressive. The surface looks like it’s been freshly oiled , but it’s completely dry and there is no tackiness at all.

Before

After

Does this seem a little obsessive? It might do, but I wanted to experiment with how what was an unusable skillet could be turned back into something to be proud of and, above all, something that could be used again, and I believe I’ve done it.

Not too shabby!

Restoring a very rusty cast iron skillet using molasses and water

When Karl’s folks were moving house a few years ago, we looked after some of their plants and garden ornaments until they were settled. A few years on and some of the plants and ornaments are still with us, because they don’t have the outside space they used to. Among the pots, I came across an old cast iron skillet which had been part of a collection of other cast iron pieces; it looked quite attractive when combined with colourful planted containers. This skillet had been outside for some years and was now extremely rusty – I brought it indoors with the idea of one day trying to restore it and for a year or more it sat on a shelf in the hallway gathering dust.

1-skillet-before-1This is how the skillet looked before it went into the solution – click for a larger version

One day I came across the suggestion that rusty cast iron can be restored by soaking it in diluted black treacle. ‘What an extraordinary idea’, I thought, and immediately sought to find out more. There is indeed quite a lot of information about restoring rusty iron with black treacle (which from now on I shall call by its American name of ‘molasses’ because it’s faster to type) and the method is popular with those restoring engine parts as the molasses solution can get into all the nooks and crannies.

1-skillet-base-before-1The width across the base is 13.5cm

So, how does it work? I went to an all-girls school that didn’t see the need to teach girls chemistry and anything I do know about chemistry I’ve learned by myself,  so it took a little while to understand, but I did find this straightforward explanation: ‘Molasses contains chelating agents. These are made of molecules that are shaped a bit like the claws of a crab – the word ‘chelating’ comes directly from the Latin word ‘chele’, meaning claw. They can envelop metal atoms on the surface of an object, trapping them and removing them’ (a bit more here). Clear enough.

I don’t really mind that I wasn’t taught chemistry, or physics for that matter, at that school – it means I’ve spent many years playing catch-up, for sure, but it’s also given me a deep sense of awe and a strong desire to find things out and make connections between them. It means I’ve lived my life in a state of almost constant amazement at how the world works and that’s no bad thing.

holcroft-1The name Holcroft is just about readable

Thomas Holcroft & Sons Ltd was a foundry in Ettingshall Road in Wolverhampton which, amongst other things, made cooking ware for Agas. It was active from the 1890s until the business closed in 1969. From the very few pictures I’ve seen, I’m guessing this skillet might date from the 1930s.

I liked the idea of using molasses partly because I was curious, but also because although the method is slow, it’s cheap (£1.15 for 454g), non-toxic and once the solution is finished with it can be tipped onto the compost heap without causing harm. Lye had been suggested, but from all that I’ve read about lye it is very corrosive and has destructive effects on living tissue. There would also be the issue of disposal. I feared it would not combine well with my accident-prone tendencies and decided lye would be better avoided. Anyway, I wanted to see what happened during the chelating process.

molasses-tinI used two tins

The urge to test this molasses/chelating idea for myself was intense so I got some molasses right away, found an old washing up bowl and used the one part molasses to ten parts water solution commonly suggested, mixed it up, put the skillet in and left it to see what happened. Every two to three weeks I’d take it out, rinse it, scrub it vigorously with a wire brush, take photographs and put it back in to soak. Each time it came out of the solution more of the rust had gone and, to my unlearned eye, it was like some strange new magic – a sugary condiment that eats rust. I’d read that the solution would smell dreadful, but was a little disappointed. It certainly smelled odd and not something to keep indoors, but it wasn’t gag-inducing. Maybe it smells different in summer when the temperature is higher.

dilute-molassesThe solution did go quite murky and mould grew on the surface

So, here’s what happens when you soak a rusty skillet in molasses solution.

2-skillet-21-days-1After 21 days

3-skillet-33-daysAfter 33 days

4-skillet-45-daysAfter 45 days

6-skillet-55-daysAfter 55 days

skillet-before-2Inside the skillet before soaking

5-skillet-53-days-edgeThe same area after 55 days

5-skillet-base-afterI didn’t know the name was also on the base until I put the skillet in a hot oven for two hours to clean off the cooked-on crud

holcroft-3The name Holcroft is now much clearer

made-in-england-3The words ‘Made in England’ also appeared and there is a patent number which I think is ‘W6392’ but I can’t be certain as it isn’t very clear

The last process was to season it. I smeared the entire skillet with lard and put it in the oven at 160C for an hour. It was allowed to cool, wiped with a rag and the process repeated twice more until the fat started to bond with the iron and the surface looked less pitted.

 5-skillet-53-days-season-1After seasoning

Having given it some seasoning, I then cooked up a pan of dry-cured, fatty streaky bacon and not one bit of it stuck to the bottom. The bacon was delicious and really crispy.

So, not bad – it went from being extremely rusty to being quite presentable and usable again. Fair enough, it took nearly two months, but time wasn’t the issue. The issue was seeing what happened and the possibility of ending up with a usable cast iron skillet. I now need to find some more rusty cast iron skillets to restore.