When you begin learning a new skill and get good enough to produce something usable, there is often a cardinal rule. Sometimes people will tell you this and sometimes you figure it out for yourself. I was never a great fan of Emeril Lagasse but once while watching his show, he imparted the cardinal rule for gravy - hot to hot, cold to cold.
Brown Gravy aka Sawmill Gravy
Put some grease in a frying pan, how much depends on the size of the pan and the amount of gravy you want to make. I would begin with the least amount possible, just enough to cover the bottom of the pan, say 1/16 inch. Raise the temperature to low medium heat. On my electric stove, this is a 3 or 4. You can add flour anytime but I would wait until the grease begins to get hot. Add flour until you create a paste. The drier the paste is the less greasy the gravy will be (obviously) but also the more difficult it will be to brown it evenly. You need to stir this mixture about constantly. How often you stir depends on the thickness and amount of heat. Of course you need to cook it until the flour colors some, most people cook it until it is brown but it doesn't have to be that dark to be done if you like it lighter. Set the pan off the heat.
The next step will be to add water or milk or a combination of the two. Personally I don't like gravy made with milk so I use water only. If you use water only, you will make brown gravy. With milk, the gravy will be white. Rather than wait until the grease and flour mixture is cool, I put a container of water in the microwave and heat it until it is hot. It is best to use a mug or something with a handle because you can easily burn yourself using a glass. The water does not have to be the exact temperature of the grease/flour but like I said - hot to hot.
Add the water to the pan and begin stirring immediately. It may look awful, no worries unless it is lumpy. If lumpy it is best to dump it and begin fresh. As far as I know the only way to get rid of lumps is to strain the gravy and this blog is about minimum mess so that option doesn't work. The reason for lumps is there was too much difference in the temperature of the water and that of the paste. If too thick, add more water - too thin - unless it is really thin, no worries. Put the gravy back on the heat, stirring about constantly and cook until it comes to a boil. It is done!
If it is too thin when it comes to a boil simply boil it until pretty close to the desired thickness is reached. Why pretty close? The gravy will thicken considerably once you pour it up.
Now the caveats. Making gravy takes some experience. The expense to make it is just about nil, so practice. If the gravy is too thin and just will not thicken, you might as well throw it out. It doesn't take too many attempts to get a feel for how much water you can add.
There are other ways of making gravy and other situations. I'll get into that in future blogs.