How can you make instant chocolate pudding come out smooth and even consistency instead of having little chocolatey clumps in it? Could something be wrong with my technique? The box says to beat pudding mix into cold milk and then whisk for 2 minutes, should be simple, right? Whisking longer doesn't seem to remove the lumps, so it must be something else.
I like to put the pudding mix in the bowl first and add the milk a little at a time, stirring or beating well after each addition, until you have smooth emulsion. Once the pudding mixture is smooth, add the rest of the milk and beat with your whisk as usual. Of course an electic mixer will help smooth it out as well.
It could be a bad quality pudding mix, improperly stored pudding mix, or a wrong ratio of mix to milk.
In the case of badly dissolving powders, you want to be more careful. You should use the proper amount of liquid - start out with around 1.5 times more liquid than powder by volume, and make a slurry. When the slurry is smooth, mix it under the rest of the liquid. This frequently helps.
Also don't store your pudding in humid places, because it can start clumping a bit in the pack. A cabinet above a stove is not a good place. You might want to find a glass jar or a tin container with a tight lid and refill from the paper package into such a container for storage. If the pudding mix is packed into individual sachets, you can place the sachets themselves in an airtight container.
Finally, it may be the brand you are buying. Food industry has means of making powders which are very easily dissolved, e.g. by using modified starch in puddings. If yours clumps too easily, they probably chose a bad type of starch. Try another manufacturer.
If you still get clumps, whisking won't get rid of them. Use a blender to break them up. An immersion blender does the job with less hassle, but a standard blender will work as well.
The classic method (which will work satisfyingly even if using pure cornstarch instead of pudding mix) is to whisk the mix (or starch) into a PART of the milk (or substitute) that you leave cold, then heat the remaining milk/liquid (including sugar and other additions), then slowly add the cold mixture to the hot liquid while at the same time whisking the combined liquid like it owes you money. This can often work even with mixes that are designed to work with shortcuts (like adding everything to cold liquid).