For basically all shoe creams and wax polishes there’s recommendations to wait 5-10 minutes after applying before one go over the shoe with a brush. It’s very common though that one don’t have the patience to follow these, and do it quicker. This is a mistake. Here’s why you should make sure to follow the recommendations.
Shoe creams and wax polishes are – interestingly enough – at the same time both very complex and very simple. Not going to go into all the nitty gritty technical details (for that, you may listen to this podcast episode), but to put it simply, when the manufacturers of shoe care products and those who write guides (and know their stuff) explains how to best use the products, there’s usually a reason for it.
One thing you’d likely have read several times is that when using shoe cream, and also wax polish, one should let the shoes rest for a while, usually 5 minutes or 5-10 minutes or so, before one go over the shoes with a brush and “set” the layer. However, it’s common that one don’t really wait that long, it feels unnecessary. Many just think “what’s the point”.
Well, the point is that in shoe cream, and to some extent also wax polish, there is water. And this water needs a bit of time to evaporate and leave only the oils and waxes on the surface. The same goes for the water used when applying wax polish (which is one of the reasons why some use “polish water”, the high alcohol-based water evaporates slightly quicker), this need time to dry before one brush it up. Cause what may happen if the small doses of water doesn’t get time to evaporate is that you embed it below the layers of wax, and as all know water isn’t leather’s best friend. One of the main points of shoe creams and waxes is to prevent moisture from getting into the leather, not the other way around. So don’t stress, take it easy and leave those layers to dry (longer than 5-10 minutes is of course fine) before brushing them up.
Here’s the large shoe care guide on Shoegazing, with most you’d need to know to do a good job.