The Vinegar water rinse will help, but also getting the dog dry is the way to go. Make sure you are also using a mild easy to rise out shampoo. Blowdrying Labradors is very helpful getting out old coat and is very much worth the investment.

When I bath my boys I use a gentle dog shampoo by Lambert Kay. I dilute the shampoo by adding 2 parts water to one part shampoo in a bottle, this makes lathering and rinsing much easier. After giving a good scrub with a zoom groom and rinsing completely I towel dry and then use my Metro dryer. By using the Metro dryer I can blow out all the dead under coat and by separating the hair with the dryer I can get a good look at the condition of their skin under all that dense coat. I never get hotspots after bathing, I'm certain that using the dryer helps. Keep in mind that dryers used for grooming animals do not run hot like hair dryers for humans, so less likely to dry out coat and skin. This is what works well for my dogs. Happy grooming!