Vertical Smoker Cooking Times

My roommate and I have a Weber Smokey Mountain Cooker, and in general, we've found that smoking times can vary a lot based on a number of different factors that tend to be hard to control. We've done beef brisket about 8 or 10 times now, and we've had some go for 8 hours and some take as long as 14.

It seems to be a function of the amount of connective tissue you need to break down. You've probably already noticed the "smoking plateau" that occurs around the 165-175 degree internal temperature mark -- when that happens there is nothing you can do but wait until the temp starts rising again and hits your target final temperature.

So to answer your question -- for larger pieces of meat, just start early and allow for wide variances in cooking times (we usually start the night before for an afternoon BBQ party). Luckily, most smoked meats taste great 3 or 4 hours after you've pulled them off (if wrapped and stored correctly). Knowing when to put on smaller pieces of meat (e.g. chicken parts/sausages/fish) will just come with experience, but since they rarely take more than an hour or two to cook, you won't be off by that much anyways.

The recommended cooking time is only a guideline. There are a variety of factors that influence cooking times in a substantive manner. For what it's worth, water in the water pan is not one of them.

The purpose of the water in the water pan is to act as a heat sink, in order to prevent temperature spikes. Anyone who claims that it helps keep what you are cooking moist should be summarily ignored. One of the more likely scenarios is that the thermometer is either inaccurate, or it is not an accurate reflection of the area in the smoker where the meat is being cooked. There are no guarantees that the temperature you read at one point is constant throughout the smoker. In fact, it is almost a certainty that the heat sink (water) will cause a cooler area in its immediate vicinity. This is pretty common in the Weber Smokey Mountain, and is why I don't use water in mine.

I would suggest some things:

1. Check the calibration of your thermometer (get a temperature reading with the probe in boiling water).
2. Put a thermometer (an oven thermometer will do) in your cooking area, to get a sense of any discrepancies between the lid and the cooking area.
3. Crank up the heat, if necessary (250f is still "low and slow").
4. Experiment with not using water, to see if that makes the heat distribution more amenable to cooking in your smoker.

Now that you have some cooks under your belt, the time is about right to tweak your methods to your liking.

You may just be smoking at too low a temperature. Don't trust the thermometer built into the lid of the smoker. Use a digital probe thermometer to monitor the air temperature near the food. A handy trick is to stick the probe through a potato--make sure you stick the probe all the way through so that the tip is out in the air. The potato will help you put the probe where you want it.