Cooking with a turkey fryer is a convenient way to try making maple syrup without investing a lot of money in a syrup pan or small evaporator.
Now that you have some sap, all you need to do is boil it to evaporate the excess water. Thinner stainless steel works best for heat transference, and any heat source that will boil water will boil sap.
Cook the sap promptly after you’ve gathered it. As spring temperatures rise, sap can spoil quickly; sap that has spoiled will have a foul odor and look milky. If you add spoiled sap to a pan of sap that is cooking, you can ruin an entire batch of syrup. Syrup that has been made from spoiled sap will be stringy and off-flavored.
If you have to store your sap because you cannot cook it right away, keep it as cold as possible, preferably in a refrigerator or freezer. You can throw out any ice that gathers on top of frozen sap, as it is mostly water.
Syrup makers often use a flat pan and a wood fire for cooking sap. To beginners who have 1 to 10 taps and don’t want to invest in a stainless steel syrup pan, we often suggest a home turkey fryer, which typically comes with a 30-quart cooking kettle and a propane burner. Turkey fryer cooking kettles don’t have as much surface cooking area as a flat syrup pan, but they can be purchased at most home improvement stores and are reasonably priced. Whatever pan or container you use, make sure that it is food grade.
Cooking with a turkey fryer is a convenient way to try making maple syrup without investing a lot of money in a syrup pan or small evaporator.
If you can keep a close watch over the cooking process, fill your pan with about 2 inches of sap. This will allow for an optimum boil. Add your heat source, and continue adding small amounts of sap as the water evaporates to maintain this 2-inch level.
If you can’t closely monitor the cooking, fill the pan with enough syrup that it won’t go dry while you are away. Come back and check it often. Never let any part of your pan that comes in contact with direct heat go dry — your pan and syrup will scorch and burn.
You can’t apply too much heat to the pan as long as there is liquid in it, but remember that the longer your sap is over the heat, the darker your finished syrup will be. Darker syrup doesn’t mean lower quality; it just means that the maple flavor might be stronger.
When your sap has reached a tenth of its original volume or has nearly reached 66 Brix (see Using a Syrup Hydrometer, page 36), you can stop adding sap. You will need to finish your sap at this point. Some syrup makers prefer to finish their syrup in a smaller pan on a heat source that is easier to control than an open fire, such as a camp stove or propane burner.
Whichever your heat source, watch your sap very closely. Some foam may develop in your pan; if it does, a drop of defoamer (see box below) will prevent the foam from getting too high. Also, make sure that the liquid in your pan is still deep enough that, as you finish cooking, your pan will not develop a dry spot and burn.
You should test your syrup at this point with a thermometer, a syrup hydrometer, or a refractometer (see Using a Refractometer, page 42).
Defoamer is typically a blend of various vegetable oils formulated specifically for the purpose of making syrup. The oil breaks up the surface tension of the boiling sap and allows the heat to escape faster, thus breaking down the foam. Defoamer can be purchased from a maple syrup supply dealer.
Sap turns into syrup when it is 7°F (4°C) above the boiling point of water. The temperature at which water boils is affected by elevation and barometric pressure. Water typically boils at 212°F (100°C) at sea level, and sap typically turns into syrup at 219°F (104°C), but you will need to test these temperatures for yourself. Each time you are about to finish a batch of syrup with a thermometer, boil some water, note the temperature at which it is boiling, and add 7°F (4°C). When your sap reaches this temperature, you have syrup.
Using a syrup hydrometer is the easiest and most accurate way to determine if your sap has turned into syrup.
Using a syrup hydrometer eliminates the need to boil water and figure out the temperature for finishing your syrup. With a hydrometer you read either the red “hot test” line or the red “cold test” line, depending on the temperature of your syrup.
A syrup hydrometer (different from a sap hydrometer) uses either the Brix or the Baume scale, both of which are used to determine the density of maple syrup. The Brix scale (more commonly used today) compares the density of maple syrup to that of a sugar solution with a known percentage of sugar. The Baume scale relates the density of syrup to a salt concentration of the same density. When the liquid measures 66 Brix or 32 Baume, it is syrup and should be removed from the heat.
Be very careful when handling a hydrometer; it is a fragile glass instrument. You may want to keep a spare on hand in case of breakage.
When you are finishing your sap, take occasional temperature readings using a thermometer to see when you are close to having syrup. When the temperature of your boiling sap reaches 5°F (3°C) above the boiling point of water, start checking it every 10 minutes with a hydrometer. The closer you get to 66 Brix, or 32 Baume, the more often you need to check.
The chart on the following page shows how incremental temperatures above the boiling point of water relate to Brix measurements on your way to making syrup. For example, if your thermometer reads 3°F (1.7°C) higher than the temperature at which your water boils, your sap is at 49.0 Brix. That’s well below the 66 Brix required for pure maple syrup.
Note: A syrup hydrometer is calibrated to read cold finished syrup at 60°F, or hot finished syrup at 211° (16°C). Don’t try to find a temperature reading for 219°F (104°C) on the hydrometer because it’s not there. It is calibrated to take into account any cooling that may happen while you fill your hydrometer cup. For hot syrup, you’ll be drawing off when the red “hot test” line on the hydrometer floats evenly with the surface of the syrup.
If the syrup temperature is significantly different from the hydrometer’s calibrated temperature, it could be due to one of the following reasons:
There are sugar sand or calcium deposits on the hydrometer. Sugar sand deposits are the grainy sediment that is created every time sap or syrup is boiled. Calcium deposits look similar to hard water deposits that sometimes form on a faucet. Carefully remove the deposits by scraping them with a knife blade or by soaking the hydrometer in a lime-removing cleaner. Rinse very well.
There is syrup sticking to the stem above the red line. This, and sugar sand deposits, both add weight to the instrument and vary its reading. Remove syrup from the hydrometer by rinsing it well with hot water. Wipe the hydrometer dry with a clean rag to ensure you’ve removed all the syrup residue.
The paper scale inside the hydrometer stem has loosened or shifted position. This is rare but does occur from time to time. Always take note of the paper’s location so you know if this happens. Try marking it with a permanent marker, and take note of the marking each time you use the hydrometer.
For the hot test take a sample of syrup directly from the boiling pan. Do not let the syrup sit or cool. Sap typically turns to syrup at 219°F (104°C), but the syrup will cool several degrees in the hydrometer cup, so the hydrometer is calibrated for 211°F (99°C).
Here’s how to read the hydrometer:
Hot Test red line is even with the syrup’s surface. Your syrup is finished. Remove it from the heat.
Hot Test red line floats above the syrup’s surface. Your sample is too heavy. Add a small amount of hot sap to your syrup to thin it and retest. If your syrup is still too thick, continue adding small amounts of hot sap and retesting until your hydrometer reads 66 Brix or 32 Baume.
Hot Test red line is buried in your syrup. The syrup is too thin, and you need to continue to boil it.
For the cold test you’ll need to use syrup that is room temperature. The Cold Test line on the hydrometer is calibrated to 60°F (16°C).
The general procedure for the cold test is the same as for the hot test:
If your syrup is too thin, bring it back to a boil, and continue cooking and retesting until it reaches 66 Brix or 32 Baume.
If your syrup is too thick, bring it back to a boil. Add a small amount of sap to your syrup to thin it, and retest. If your syrup is still too thick, continue adding small amounts of sap and retesting until your hydrometer reads 66 Brix or 32 Baume.
A refractometer is another tool used to measure the sugar content in sap and syrup. A refractometer measures the refractive index of the syrup, or how light bends as it passes through the syrup. There are some advantages to using a refractometer rather than a syrup hydrometer, but a refractometer is considerably more expensive. To use one:
When measuring hot syrup, the only real benefit to using a refractometer rather than a hydrometer is that less syrup is required for the refractometer. The instruments are equally accurate.
When measuring room-temperature syrup, a refractometer works more quickly than a hydrometer. It takes time for a hydrometer to stabilize in cold or room-temperature syrup. With a refractometer, there is no wait for an accurate measurement.
A refractometer is another tool for testing the sugar content of sap and syrup.
We are often asked by customers if they can test their syrup with the same hydrometer or refractometer they already own for making alcohols such as wine or beer. The instruments for alcohol making and syrup making are calibrated differently. It may be possible to convert the numbers, but it’s probably quicker and easier to have a hydrometer specific to the task. Syrup hydrometers and refractometers can be purchased from a maple syrup supply dealer.