Alcohol
There are certain alcoholic drinks that contain sugar and can increase mucous production, but not all of them do. Nevertheless, they ALL have alcohol, and that’s a problem all by itself. Alcohol relaxes your muscles at the back of the throat, making you more likely to snore.
And while it doesn’t cause phlegm to produce, it does loosen those muscles. Drinking right before going to bed is very likely to make you snore. If you want to drink but don’t want to keep your entire house awake, then make sure you stop consuming alcohol at least three hours before going to sleep.