I have only just started trying scratch recipes, and after a long research project here, I think I have picked out a few of the ones many have given high marks. But, I still find myself longing for that more moist consistency of doctored boxed mixes!
In recipes that call for buttermilk (which most of the scratch recipes I have call for), would subbing sour cream make any difference in the moisture of the cake? If so, what would be the ratio of substitution?
Buttermilk is a thin liquid while sour cream has a thick consistency with no standard for the product. So one brand will differ from the next. Since you are new to scratch baking, I don't advise making any recipe substitutions until you are familiar with the process. Plus, we all bake differently, so I never make a recipe change without first making it exactly the way it is written. This helps me know if it's a good recipe for my style.
In baking formulas sugar=moisture. So (after trying the recipe first as written as the pp suggested) try adding more sugar to boost the moisture. Corn syrup gives moisture just like sugar, but does not impart nearly as much sweetness so you could try adding that too.
KoryAK thank you for that information--I did not know that!
If I find a batter is a little too runny, making it slightly unstable, I sub sour cream for the buttermilk. Moisture comes from many factors. If it isn't moist enough with buttermilk, my favorite, get a new recipe. I am not a fan of sweet desserts so I don't add sugar. But that is just me.
What flavor are you trying? Make sure you have an independent thermometer that is calibrated. Mimi, is it you that knows the sugar test? I personally periodically put all of my thermometers in one oven (I have 4). If they read the same, the odds are that they are calibrated. I only use spring thermometers because digital can be uncalibrated by a long shot on a moments notice. The sugar test uses browning sugar to test. Just google it.
The wrong temp can rob a cake of its moisture. Also, many cakes can come out with a few damp crumbs on the toothpick, as the cake is still baking for a few minutes out of the oven.
Don't worry about experimenting. All scratch bakers must adjust and get to know the recipes. This is the stage that looses many bakers. You have to be able to bake and adjust until it's right. Sometimes I bake one experimental recipe 7 times in one night. And then all of a sudden... wow happens. This is the payoff for the work. But then you have that recipe forever.
Let us know how things work out. We can always use another scratch convert.