A Bluebird Day

I try to make a point of getting out into the T.A. Forest at least once a week during a prep block to check trail cameras and note any new happenings in the woods. While walking on the Eastern Trail on a recent warm afternoon, I spotted a small flock of eastern bluebirds (Sialia sialis) feeding along the wood line. Bluebirds are insectivores who generally don't show up until insect numbers are sufficient in the springtime. There are always early arrivals and a select few that will actually hang on for the winter here in Southern Maine. I had a small flock hang around my feeder persisting off suet and sunflower seeds last winter.

The flash of blue from the male against the drab early spring landscape is hard to miss and I was excited to see this omen of spring. The timing of the sighting also lined up well with some vocabulary we have been learning in Maine Fish and Wildlife class. Sexual Dimorphism occurs when there is a distinct difference in appearance between male and female members of the same species. Eastern bluebirds are a classic example of a bird exhibiting sexual dimorphism. Mallard ducks, northern cardinals, and wild turkeys are all examples of Maine bird species exhibiting this trait. As with most sexually dimorphic birds, the male eastern bluebird is more brightly colored. It is assumed that this difference in appearance is a result of tens of thousands of years of natural selection. Females selecting for the bluest of males have created the intense coloration seen today. Because females do the choosing, their coloration has not become as intense as the males'.

 A female eastern bluebird perched on a branch above the Eastern Trail

A male eastern bluebird perched on the eastern trail field fence watching for insects along the ground

Crunch Time: Finishing Your Maple Syrup

Nothing strikes fear into the heart of a maple producer more than getting side tracked in the final moments of syrup production and cooking sugar onto the pan. This not only makes a mess that is hard to clean up but also can ruin the flavor of your entire batch. With the amount of preparation and manual labor that goes into sap collection and boiling, losing the batch at the final moments can be devastating. During my high school and college days working at Snell Family Farm during maple season, boiling was an evening ritual that felt like a reward for hard work earlier in the day. We would spend the evening stoking the wood fired evaporator and telling stories. As the thermometer in the finishing pan began to creep toward 219 degrees Fahrenheit (the boiling point of syrup), things got considerably more serious. The finished product had to be removed from the heat and filtered immediately or else BAD things could happen.

A close eye is kept on the thermometer in the final moments of syrup production.

I "finished" our first pint of syrup in class this past Monday and we were all able to enjoy warm maple syrup over ice cream. Saying syrup boils at 219 degrees Fahrenheit is a little oversimplified. In fact, maple syrup boils 7.1 degrees Fahrenheit above the boiling point of water. We generally think of the boiling point of water as 212 degrees Fahrenheit but this is a moving target. Elevation and barometric pressure can affect the boiling point of water and thus move the syrup target up or down.

Using they hydrometer to confirm our syrup is finished

Sap that has not yet reached the sugar concentration required to be called syrup can spoil quickly so it is important to confirm in a couple of ways that the syrup is truly finished. Another measurement that can confirm we have reached syrup is density. A nifty little tool known as a hydrometer uses principles of buoyancy to measure the density of a fluid. Maple sugar producers use a hydrometer calibrated for syrup to help confirm their product is finished. After hitting 219 degrees Fahrenheit in class, we tested our syrup using a hydrometer and confirmed we were done.

Filtering the final product

Finally, the hot syrup was poured through a filter consisting of a synthetic filter paper and multiple layers of cheese cloth. This removes all of the mineral, mostly potassium nitrate, that has concentrated in the syrup along with the sugar. Maple producers call this cloudy mineral sugar sand or niter. Finished syrup should be free of sugar sand and bottled hot to ensure there is no contamination in the container. We let our new jug of syrup cool for a few minutes before enjoying a long awaited taste of spring.

A sweet reward

The Finished Product

Thursday was a long day of boiling but with a sweet reward when all was said and done. I got our mini evaporator set up just below my classroom window first thing in the morning. I teach freshman chemistry during first block and this process provided a great teachable moment. The timing of the boil could not have been more perfect as we are currently learning about classifying matter and separating mixtures. I presented them with a 5 gallon bucket full to the top with what looks like water. It took a little convincing but they eventually believed me that around 2.5% of the bucket was actually sugar! After a bit of brainstorming, their experiment was in place. Maybe, by boiling the sap, we can remove the water leaving the sugar behind? Perfect, it was out the door to start our boil. I can't lie, it was a little anticlimactic after dumping the cold sap into the pan and standing there for a few minutes staring at a lifeless pot. I can't wait to show them the finished product first thing Monday morning.

Raw sap just after collection earlier last week. (Photo by Julie Vail)

Before long it was second block, my Trees and the Maine Forest upperclassmen were arriving, and the pan was rolling. At this point in the boil, the sap was still very dilute but their was a faint yet familiar smell rising from the steam. We had a great time standing around the pan in the ice cold breeze talking about the ins and outs of maple production.

Steam rises from the pan during our first boil of the year. (Photo by Julie Vail)

Over the course of the day, the sap level in the pan would drop and more would be added. Slowly, the sap began to darken and the steam began to smell sweeter and sweeter. Sometime around the end of third block I was able to bring what was left inside to finish boiling in my classroom. People were following their noses into the room to find the source such a sweet aroma. I was bottling finished maple syrup just as the final bell rang. Stay tuned for a post detailing the finishing process.

Our first batch of syrup this season.