I brewed a Wit last spring that was suppose to have an OG of 1.050. It ended up at 1.044 but was very good none the less. My question is do I adjust the recipe to have it at 1.044 or do I keep it the same and adjust later?
What did you figure your efficiency was? Have you done other brews with about the same? I generally bump up most recipes by an extra pound or so of base malt and stop the sparge as soon as I get what I need. It wastes a little grain but I NEVER undershoot my gravity.
If your efficiency is VERY low, like 60% or less you might have issues with your crush, sparge technique, temperature control or water chemistry....
If the recipe was assuming 75% efficiency at 1.05, and you reached 1.04, then you had a 66% efficiency.
The idea is to keep all of the variables in YOUR process consistent, which will give you a consistent efficiency number for your process/equipment.
So, keep track of your numbers for 3-5 batches, calculate your efficiency on each, then average those numbers to get a pretty good idea of the efficiency of your process/equipment.
Most recipes are then calculated for a 75% efficiency. If your average efficiency is 66%, and you want to duplicate a recipe that's assuming 75% efficiency, you'd need to add proportionally more grain to the recipe for your process to produce the same recipe.
Hope that makes sense. It's more about aiming for consistency than it is trying to bump up the efficiency.
Here's a good article to read that goes into more depth: