The answer is -- as many as your smoker will hold. You can double, triple or quadruple this recipe as many times as you like, as long as it will fit in your smoker. You do not want the pretzels to soak in butter, so I recommend only mixing up what will fit in the smoker. As you increase the number of pretzels, you may have to increase the smoking time slightly. In this case, check your pretzels frequently after the 20 minute mark to prevent burning.