I'm new to the forum and fairly new to smoking in general. So far I have 3 pork shoulders, a whole packer brisket and a pair of turkey's under my belt.
Just so you have a frame of reference, I'm cooking with a WSM 22.5 and monitoring my temps with a Maverick ET 732 and the temperature maintenance is being assisted by a Pitmaster IQ 110.
My "problem", if it even is one, is that I see a lot of people claiming 1 1/2 hours per pound for pork shoulder but none of mine see to adhere to that general rule. In fact I'm generally much closer to 2.5-3 hours per pound. My method of operation is to use the minion method and pour about a gallon or maybe more of boiling water into my WSM water pan. Once the initial billowing has calmed and the pit temp has stabilized at the temp I want to cook at (225) for at least 10 minutes then I will throw my pork shoulders on the upper grate. I place my meat probe and set the pit probe so that it is near the center of the grate but at least a few inches from it so that the meat doesn't throw off the temp reading. After this I toss in a chunk of whatever wood that I want to add and then forget about it for the next 1 1/2 - 2 1/2 hours which then I will add another chunk of wood. Then It's forgotten again for about another 10 hours which is when I need to add more fuel usually. I typically use Royal Oak lump by the way. I then set and forget again only occasionally adding more fuel here and there but I try to make it very quick so that it doesn't disrupt the pit temp too much. I can typically add more fuel in a matter of seconds. The entire cook time I am able to maintain a very steady temperature between 215-240. I cook until around the meat is about 190 but I've already discovered that sometimes the meat is ready before that and sometimes after that temp so I also use the probe tender and/or the bone wiggle test. All of my pork shoulders have been a minimum of 8lbs and maximum of 9.5lbs yet I have yet to have a cook time of less than 24 hours. My last one actually took 28 hours to reach 187.
My brisket also took a fair amount of time longer than the "typical" but unfortunately I don't remember enough details from the cook. My set up process was essentially the same though and I do remember the I kept the water filled with boiled water throughout most of the cook. I want to say it took about 6 hours longer than the "norm".
How unusual is it for a pork shoulder to take this long? Is there something flawed in my process? Thanks for your help guys.
p.s. I forgot to mention that in preparation I leave the fat cap on and also inject the shoulders at least a few hours prior to putting them on the grill... fat side down. With the exception of the brisket (a little too tough for my intentions) everything I've smoked has come out exactly as planned and been absolutely fantastic tasting.