Ok, now that you've got a handle on temperature (see my previous post), the next step is to take control of moisture. Unlike temperature, moisture won't be an issue most of the time. Most cakes, cupcakes or cookies don't really need a big control of moisture...they contain their own in the form of butter or other liquids, and manager quite nicely if left alone. Other things don't...custards, cheescakes, flourless cakes, and most breads.
Commerical ovens have elaborate systems for keeping a particular mositure level in an oven for baking particular things. However, the simplest and easiest method is to use a bain marie.
Bain marie is French for water bath, and the term applies to anything in which water is used as an insulator. Large steam tables at cafeterias, double boilers, and casseroles of water in your oven are all bain marie. The one we're concerned with here is the last one. One mistake people often make is to think that the purpose of a water bath is to release steam. It is...to a degree. But more importantly, it's to help insulate. For example, things like little individual custards. With those, controlling moisture is essential. If you watch the TV cooking shows, they normally show them going into the oven while sitting in an extra pan of water. What that does is lower the cooking temp. See, water CANNOT heat above 212F...the boiling point of water. This means that the parts of the dessert most in contact with the water will cook at a lower, more gentle temperature. Sure, you need the additional steam that the water will generate as well...part of what keeps cheesecakes from cracking during baking is simple steam. But the insulation is the more important aspect here.
A water bath is simplicity itself...simply use a container with deep sides large enough to hold your actual baking pan. Add hot water deep enough to come halfway up the sides of your baking container, and you're good. MAKE SURE the water is hot or boiling when you start the baking process, or you'll completley throw off the baking times...the oven will have to heat the water as well as the product if you use cold or cool water. If the water is hot, it acts almost like a baking stone itself, helping keep the heat inside the oven consistent, and consistently gentle.
Steam is the final element in what I consider the basics of baking. There are times when you need steam, but not a bain marie - most particularly during bread baking. It's just not that hard to generate...let me explain how I rig it up in my own minimally equipped kitchen.
You can use two methods...for simple steam, place a cast iron skillet in the bottom of your oven. After it preheats, and the skillet itself is hot, then fill it with ice water when you place your dough or bread in the oven. The skillet stays hot enough to do this because of the properties of cast iron itself. Easy as that...the water will gently heat and steam, helping ensure soft exteriors on breads, such as plain white sandwich bread, which is absolutely AMAZING when homemade.
If you want a crispy crust, then the secret weapon is a spray bottle as well as the skillet of water. Gently misting the exterior of the bread at 3 minute intervals for the first few minutes of cooking will ensure the exterior stays flexible enough for the yeast to do its thing...expanding as the bread rises in the heat. Stopping this step will allow the crust to set, and subsequently turn golden and crispy, which will contrast beautifully with the chewy inside. In a nutshell, y'all - THAT'S the trick to great bread.
So there you are...I wanted to give you more than just a trick...I wanted to give you the 'whys' - which is the first step in taking control. Once you know how to prevent problems to begin with, you won't need all the stuff to correct them. Your relationship with your oven comes first...and subsequently what you develop with your baked goods will be far more smooth and successful. Think of the head of a dysfunctional family who says 'enough!' That's you - take charge. You'll love what you end up with. ENJOY!!!