After I recrystallize a floor the white grout is turning yellow. How do I remove this yellowing and more importantly how do I prevent it from happening?

The yellowing is caused by the steel wool you are using reacting with the recrystallization fluid. It may also be from the waxes that may be found in the recrystallization fluid. To remove the yellow color you will have to scrap the grout with a grout saw. It may not be necessary to remove the grout. A light scraping will sometimes remove the yellowing. To prevent the yellowing try using a synthetic pad rather then steel wool. You may also want to try switching to another brand of recrystallization fluid.

TIP Also, make sure the floor is dry. If you hone the floor, you should allow at least 24 hours for it to dry.