Originally Posted by jldc
I'm not talking about wholesale changes (different hops/yeast for example). I figure that as long as I stay close, it will still be beer and still be drinkable, right?
Even if you don't stay close, it will still be beer for sure, and most likely drinkable as well :-)
It's really pretty hard to mess beer up. If you change a recipe, the result might be less tasty, but it might also be delicious. After all, every one of those classic styles once started with a single brewer thinking "hmm, I wonder what would happen if..."
The thing I find most helpful about brewing software is how it helps you understand what the effect of your changes will be. For instance, dry versus liquid extract will provide a different amount of fermentables for the same weight, so to keep the end alcohol the same, you will want to adjust the quantity when changing one to the other. Software makes it easy to see how the final alcohol changes as you alter things like that.
Likewise if you move your extract to a late addition, the main change will be you will get more bitterness out of your early hop additions. That could be a good or bad thing, depending on whether you want to tweak the recipe to make it more or less bitter, or just keep it the same. Fortunately, the software will calculate a predicted IBU, so you can see how this changes when you select a late extract addition, and adjust the quantity of bittering hops if you want to balance this back the other way. Maybe you want to use late extract so you can get more bitterness in your brew from the same amount of hops, or maybe you want it so you can save money by using less hops while keeping bitterness the same - either way the software makes it easy to understand what is going on.
And don't be afraid of making bigger changes like altering the hop or yeast varieties. Just make sure you understand WHY
you are making these changes. Beer Smith includes descriptions of all the ingredients, and you can find much more info in places like the White Labs or Wyeast website. It can be a lot of fun to experiment with different kinds of yeast, as long as you know what you want the final beer to taste like, and choose something that sounds like it would fit. It wouldn't be too smart to pick a fruity English yeast if you're going for a super clean end product, for instance, but if you're looking for fruityness, there are dozens of subtly different fruity yeast styles out there, and the only way to know which you prefer is to try them all!