During a disaster, the value of currency is often diminished, but certain commodities become far more valuable. The law of supply and demand tells us that when supply of a desirable resource is low, demand skyrockets, and the worth of that resource increases. When polite society comes to a grinding halt and people are fighting for their lives, it's reasonable to assume that food, weapons, and comfort items will be in high demand.
You may have already thought to stock up on freeze-dried food and ammunition, but have you considered that third category? Alcohol is a comfort item which may become an important bartering resource during emergencies, especially if major breweries and distilleries shut down. And if having a fully-stocked bar is valuable, knowing how to produce a continuous supply of liquor is even more valuable. With a little trial and error and the right ingredients, you can whip up a batch of booze that can be traded for other items you need.
Fortunately, there are countless ways to make alcohol from a variety of simple ingredients. Even if all you've got is tree sap or stale bread, you can ferment these ingredients into alcohol. The following infographic from WineBags.com shows the ingredients and processes used to make 48 different types of booze.
Despite its length, this is by no means a complete guide. There are many, many more types of alcohol beyond this list — you can probably think of a few off the top of your head. It just goes to show that no matter the scarcity of raw ingredients and natural resources, humans will eventually find a way to make alcohol, and other humans will want to drink it.