Hi Mas and welcome to the forum. There are several of us from the UK who chat regularly on here. Where in London are you? I am in Kent.
Before we can specifically answer your temperature control question we need to know what type of BBQ/Smoker you are using. In general though the temperature control is about managing the air entering the bottom/side of the smoker so that the charcoal burns at a restricted rate. This usually involves managing the bottom vents and, depending on the temperature you are trying to maintain, may also involve starting with a mix of unlit and lit coals in your charcoal tray.
Give us a few more details and we can be more specific regarding your BBQ/Smoker.
Im actually in Dartford....close enough to London to not make a difference :)
The smoker i have is only a very entry level one, it has two doors, one bottom , one midway and a vent outlet at the top next to the temp gauge. The charcoal tray is flat round in the base with no ventilation. I have read on another forum that perhaps i should drill out some vent holes into the charcoal "tray side" ?
I do have a coal chimney for starting the coals of, so they are burning well a the start, but i do not seem tpo be able to get above 150 F ?
I am using restaurant grade lumpwood charcoal.
Does the amount of water in the tray have any real effect on temp?
Welcome to the site, any chance of you posting a pic or two of the smoker. And yes water will make it harder for your smoker to reach temps. It will also help maintain the temp for a longer period of time. It's a trade off you'll have to make.
Hi Mas - I was brought up in Joydens Wood and went to Dartford Tech - now Wilmington Grammar :-). Dartford was my old stomping ground quite a few years ago - LOL
From your description it sounds like you have one similar to this
These are very common and they can be quite challenging when it comes to fine temperature control. As you suggest the biggest problem is air control over the coals - some provide too much which leads to a very hot cooking chamber and others do not allow enough air to reach the charcoal resulting in them running too cool. It sounds like your problem is the latter. One of the smokers who came to the UK smokers weekend in Billing Aquadrome last month brought one of these and we helped him to achieve a reasonable amount of temperature control without making physical modifications to the smoker itself.
Drilling holes in the bottom would certainly help with the air flow however this would not give you any fine control without also adding an adjustable vent control. If you can take a few photos of the inside of your smoker - water pan and charcoal bowl and any bottom air vents - we can help you more specifically. Sometimes it is simply a case of adding a mesh grate in your fire bowl to lift the coals up and let air get underneath them.
Yes, water in the water tray will affect the temperature that the cooking area reaches. The water tray itself (even when empty) acts as a heat baffle that protects the food from direct heat radiation from the coals. Just because it is there it does not mean that it has to have water in it. Some people use sand in place of water - or just leave it empty.
For low-and-slow cooking water in the bowl will help a smoker stabilise at or around 100-110 C (212-230 F), however if you are looking to achieve higher hot smoking/roasting temperatures of 160 C (320 F) then it will certainly make the higher temperatures more challenging to achieve.
yes my unit is almost identical, and yes i learnt the lesson about the top vent early on in experiments.
Im going to try putting a few holes in the sidewall of the charcoal tray and going forward fabricate a ring of stainless to make it adjustable ( im a sheet metal worker) . Going to have a trial smoke today to see what effect the holes have on temp, as was struggling to get above 130 F yesterday, although the salmon fillets turned out great.