Best cooking surfaces and lighting a fire for long, slow cooks

Good morning...

After a ridiculously full on couple of days shooting my next book - 25 recipes over two days, one of them persistently grim and rainy - today is just short little newsletter featuring three questions I’ve had in my inbox over the last week or so.

Gerry wants to know about cooking surfaces…

I’ve had one of those lovely Netherton foundry chapa things last year - so gorgeous but so far I’ve just oiled it and it’s sitting in the lounge! So a question might be around cooking surfaces - what differences between iron (can you still get indirect heat effectively with iron?), stainless steel and those fancy planks of wood you get from garden centres for the bbq? And does the cooking contact surface affect the sear or not to sear or marinated protein/veg? 

Firstly, I love the fact you store your fire table in the lounge (Netherton’s stuff is certainly pretty to look at, see mine above) but really you just have to get on and light it lad! 

Generally I would only use standard stainless steel grill bars in my barbecues - so on my Weber’s and Kamado’s I have never used any of the cast iron inserts that came with, they are busy gathering dust in the shed. Not that cast iron is bad necessarily but more that stainless does the job perfectly well. Those of you that have SEARED may have read about my dislike for grill bar marks, and how the goal for searing is always to get an evenly browned crust rather than parallel stripes (this is the Maillard reaction - a big meaty subject for another day). Stainless gives you a very decent sear. Consider that lit charcoal is around 500 plus Celsius, and that heat transfers very quickly into the conductible surfaces (conduction heat innit?) and over time they would equalise to be the same temperature as the charcoal. That’s going to happen whether its steel or iron. In theory iron will hold the heat for a little longer and steel will heat a little quicker but if your fires going strong and your searing a steak over hot direct heat its going to be bastard hot regardless. 

Ditto slower indirect cooking - over time the heat transfers from the infrared radiation created by the lit fuel to the conduction heat created by the metal surfaces and the temperatures will equalise. Doesn’t matter if its iron or steel. With indirect cooking you would almost always be cooking with the lid down (think oven!) and the main heat that’s cooking your food are convection currents, or hot air, so the cooking surface is pretty irrelevant. 

So stainless or cast iron is basically a personal or design choice, or just simply what your BBQ came with. Netherton’s wonderful iron fire table is sturdy and will last a lifetime, designed to be kept outside, get weathered, burn and brushed off before you use it. 

Planks of wood? I don’t use them, don’t see the point really, preferring to cook on metal surfaces and add wood smoke via actual burning of wood, but maybe I will give them a try one day…

Will wants to know about fire management for long, slow cooks…

How do you manage your fire on long, slow cooks? Last week I did your pulled pork recipe from Seared on my weber kettle, and it turned out perfect, but I probably lit my chimney starter 4 times, moving charcoal back and forth between the bbq and kettle to try to keep at 130C. Should I be using lumpwood charcoal for this or briquettes, and is there any secret way to set up a really slow efficient fire?

Glad the pork was perfect Will! Managing a fire for slow cooks is all about mastering the oxygen. More airflow gives you a hotter quicker burn and less airflow gives you a slower, cooler burn. So with a long slow cook you want to be shutting your vents right down to achieve the heat you need whilst prolonging the burn time.

On a Kamado style barbecue you have very fine control of the oxygen, so you fully load with charcoal and then the vents do all the work, slowly burning the fuel out from a lit fire spot so the fuel gets lit gradually over a prolonged period of time (this is why very pure fuel is needed - you definitely don’t want to be slow burning toxic chemicals whilst your food is in situ. And you don’t want to be burning crap charcoal, full stop). 

With a kettle barbecue you naturally have less fine oxygen control (they are just more leaky air-wise) so will always need to top up with charcoal during the cook. If you were to add a lot of charcoal at the beginning you would struggle to keep the heat down low. Lit fuel has a certain capacity for heat energy. So a handful of fuel will generate so much heat, whereas two handfuls will generate twice as much heat. So if you need a cooler temperature you have no choice but to start with less fuel and add more during the cook to keep the heat level even.

One of the best things about pure lumpwood is that you just add it in a lump at a time to keep the temperature even. You shouldn’t need to heat more in a chimney and transfer, just add a lump or two to the lit fire every now and then. How often depends on lots of things - air temp, dampness, wind, fuel, how much control of the oxygen you have - I can’t give a definitive formula. So with a kettle there is definitely more fire ‘babysitting’ that goes on, which you need to see as part of the fun of the process.

Briquettes? Nearly always made with shit charcoal so goes with saying that I don’t use them. But Whittle and Flame do make their Whittle Bricks that I do occasionally use - just one snapped into 3 bits and added to a lumpwood fire will slow the burn down and create a longer more sustained heat. I don’t use them on their own without lumpwood as they are a bit piggish to light. Also, some charcoals are naturally slower burning (and therefore can be harder to light initially). Oak for example, harder to light, burns for longer as the carbon is more densely packed, so would be a good choice for long cooks.

And finally, Dan wants to know about veg appropriate smoking woods…

Just curious to what chunks of wood you use to smoke veggies?

Short answer - use whichever wood you fancy! I have long argued that different woods smokes, whilst they smell different, don’t strongly taste different on food. By the time you’ve added a rub or marinade, or added a dressing or sprinkle of herbs post cook, the taste you get from the smoke is a little subtle layer of flavour on the food. So concentrate more on the level of smoke you like. Smoke tolerance is much like salt or chilli tolerance - some people like more, some people like less. Personally I like a fairly light smoke as I want the all the other flavours to shine. And I don’t want everything to taste smoky (ie taste the same) so very often I wouldn’t add wood at all. If I’m smoking I tend to use oak, cherry or apple because that’s what I have… but I wouldn’t really worry too much about which one I grabbed for different types of food.

And that’s is for today, hope helpful. If you’re a paid subscriber look out for some behind the scenes stuff on the book shoot next week - I may even share some top secret snaps from the book as long as nobody tells my publisher ;-)

Big love,

GT

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