In many places in the northeast and midwest, maple syrup season signals the start of spring, and there's no replacement for real, natural maple syrup. After you have it, those high fructose laden "pancake syrups" that you see in the grocery store will never do.
Step 1: Find Your Trees
Start off by finding a tree. There are several types of maples, and although the sugar maple is the best because it has the highest sugar content, any maple tree will work. A maple tree should have leaves and seeds that look like this. There are also many websites that can help you identify a maple by the bark. (Thanks to www.massmaple.org for the pic). The tree needs to be a minimum of 12" in diameter, and if your tree is more than 20" in diameter it can take two taps.
Many other trees other than maples can be used. Pecan trees make a fabulous syrup, but I've heard of people using sweet gum, birch, box elder, among others. Each species will have it's own unique flavor.
Step 2: Add the Spiles
Get your spile (the tap that goes into the tree). These are only a couple of bucks apiece and can be found all over the internet. You will want to drill a hole, typically 5/16" (the spile will tell you what size to drill) a couple of inches deep into the trunk. Try to drill about chest height, and drill slightly upward to help the sap drip downward. Then, using a small hammer or mallet, drive the spile into hole you drilled. A one gallon bucket works well for me, but you can use any size you like. Just remember, the larger the bucket the less frequently you'll need to empty it, but the heavier it will be.
Some large scale producers use hoses and vacuum lines to pull the sap from the tree and to a storage tank, but if you're only tapping a few trees in your backyard, that isn't necessary.
Step 3: Collect Sap
The sap will be clear, and will taste like water with a very slight sweetness to it. Sap flows the best when it gets into the 40s during the day but below freezing at night. I've been known to get 3 gallons from a tree on a good day, and less than a quart the next. It all depends on the weather.
You'll want to store the sap until you have several gallons to work with. I recommend checking the buckets a minimum of once a day, and dumping it into a large food grade container and storing it in a fridge or freezer. It will take a LOT of sap to make a little bit of syrup.
Step 4: Boil It Down
It takes about 40 gallons of syrup to make a gallon of syrup. This varies depending on the sugar content of the sap, but this is a good rough estimate.
Professionals have a "sugar shack" with a huge, flat vessel for the sap. They build a fire under the vessel to boil it down. I only have 2 trees tapped, so I am not going to that extreme. I use a propane fired turkey fryer. I get about 10 gallons of sap and start boiling. Be aware, if you do this on the stove, this creates a LOT of steam, and you can make every surface in your house sticky. I've even heard of people boiling huge pots inside and water logging the drywall on the ceiling. If you don't have a pot big enough, remember you can continue to dump in more sap as it boils down. Once it starts to thicken, you can bring in the maple concentrate and finish on the stove if you like.
As it boils, the sugar concentrates and begins to caramelize making that dark brown color. As the water boils off, the boiling point of the liquid increases. When the liquid reaches 7 degrees above the boiling point of water in your area (219 degrees F at sea level) it's done. Me, I just boil it until it's thick and tastes good.
Step 5: Finishing/storing
Once it's syrup, you can pour it into bottles and keep it in the fridge.
For long term storage, you can pour it into sterilized mason jars and put into a boiling bath canner. Contact your local extension office for times in your area.