How do you know whether a cake needs refrigeration or not?
I never know if I'm doing the right thing when I decide to refrigerate some cakes, but not others. Which cakes taste/preserve better refrigerated or need to be refrigerated due to their ingredients vs. which cakes do better stored at room temperature?
For me, it depends more on the frosting/fillings. Whipped cream type frosting or custard like fillings are refrigerated. As the cakes themselves, butter doesn't refrigerate as well as oil, but I personally like the denser taste of refrigerated butter cakes. But, it turns some people off so you need to let it come to room temperature. So, no easy answer, it's a combination of many things, including how many days.
I think every cake is better *preserved* by refrigeration -- but should be covered properly, and brought to room temperature before eating.
My rule of thumb is to refrigerate cakes like cheesecake or with fresh fruits in them: apples, pears, etc, but not dried fruit. I also refrigerate cakes frosted with cream cheese, and maybe chocolate, if the temperature is warm merely so that they don't melt. Otherwise, my cakes are stored on the countertop. I generally don't really like refrigerated cake because they tend to stiffen up from the cold especially those that are made with butter so I remove them before serving to bring them to room temp. Unless you plan on making a cake a week in advance, there are not many that needs refrigerating.
Refrigeration preserves frostings and fillings that would otherwise spoil, but it isn't so kind to the cake itself. My general rule is to refrigerate any cake that has a whipped cream or cream cheese frosting, or a custard filling. In these cases, the danger of food poisoning outweighs the risk of making the cake too dry. If the cake just has a basic butter-sugar-flavoring frosting, then I leave it out unless it's' summer and my kitchen is really hot.
Because refrigeration involves dehumidifying the air to cool it, refrigerating a cake is generally a bad idea. Even very well covered cakes will dehydrate to some degree in the refrigerator and, as pointed on previously, a cake that has been refrigerated must be brought back to room temperature for serving if it is to be enjoyed fully.
"Cheese cake" is not actually a cake, it's a cheese custard so it doesn't fall within the category. But even cheese cake must be well covered (air tight seal) to hold up well under refrigeration.
Frankly, I'd rather cover my cakes and allow them to stand at room temperature (covered of course) for a day or two and then discard the unused portion (rear in my house) rather than refrigerate them.
Reducing the size of the cake helps with ensuring that it's consumed in good time thereby eliminating the need to consider anything beyond counter storage.