Old Sap = Reduced Yield? Need advice...

[user587]

I was out on spring break with the family last week (priority for me is family-then-syrup), so I missed most of the nice late run in Michigan. During my absence, my new helper-buddies did a boil for me (HUGE help and thanks!) with over 500 gal. They boiled like normal, but got only about 4 gal. of syrup. The sap boiled was brought by a guy who has brought sap many times before this season, he reported 1.8%, which is the same as every other batch of sap before. Also we checked the sap remained and found it to be between 1.5-2%. Previous boils have yielded syrup in the ratio expected by the rule of 86. But this boil is WAY off. I looked at the notes, and the boil was indeed 500 gal., and there is indeed only a few gallons of syrup pulled.

The sap boiled measurement is accurate - before the season I calibrated the feeder tank, and the feeder tank is how we measure the sap boiled. The sweet in the pans before and after was pretty much the same, within a gal. or so. All measuring was done similar to previous boils, and the ratios have all been as expected before this boil. The only difference for this boil was that the sap was several days old (approx. 5-7 days from tree to evaporator) and somewhat cloudy. Also some of the firewood was a bit green, but dry wood was mixed to keep the stack temp and boil rate approx. the same as before. The syrup is dark, but the flavor is actually pretty decent, fine for our personal use.

But 500 gal. sap for 4 gal syrup? Is this a result of old sap? we're scratching our heads...

Now I've returned home and have 320 gallons of cloudy sap in holding tank (it actually has a slight odor, I'm worried about it) and a few hundred gallons more sap which has been hanging in trees for the past week. I know it should probably be dumped, but if the "only" problem with boiling old sap is the dark color and heavy/burnt flavor, I've been thinking I may boil it and keep it for personal use. But if 500 gal. sap will yield only 4 gal. syrup, forget it.

Any advice? Thanks in advance for your thoughts...

[Ausable]

Howdy user587 - I would say - it is always about the sugar content of the sap at time of boil and nothing else. The sugar content will vary at different times of the season and from tree to tree. But - if at time of boil - your holding or feed tank is checked for sugar content of the sap - that is how the numbers will work out for the gallons of syrup produced by the boil. I hate to say it ----- but that aaaaa sap your friends boiled had to have had the lowest sugar content ever recorded for maple sap in history. Kinda like Bar Whiskey --- watered down - a lot ---- Mike

[PerryW]

It could have been that when they started the boiling the 500 gallons of sap, that the evaporator did not have much "sweet" in it because you had a big just before you shut down from the previous boil.

Or when you ended boiling the 500 gallons, you stopped just before you were about to have a big take0off.

[3rdgen.maple]

That figures out to be around .7 percent sugar content. If you read between 1.5 and 2 % that as left in the tank then someone messed up and isnt telling you about it. Spilled sap, burn batch, something.

[danno]

Regarding the cloudy sap, I'd boil it. I've made very good flavored, dark syrup from pretty scary looking sap.

[user587]

mystery solved - the flue pan was set up with the sap inflow and outflow on the same side, so the flue pan did not have through-flow. Thankfully it did not make it to syrup, but there was some stroooong sweet in the flue pan. Found all of the missing syrup, after all.

Thanks for the responses.

[BobU]

Sounds like your helpers were useing your evaporator like a big batch pan.

Should be fun pulling syrup off on the next boil, once you get the gradient straightened out.

[user587]

It was not that bad - we pulled a huge batch off the front pan to get the heavy stuff out of the rear, and all went well. Essentially, they had two parallel boils going, both in divided pans, and both being fed raw sap. They pulled some off the front (at a rate much lower than normal), but the rear pan *thankfully* never got to a point to have finished syrup due to it's much greater capacity. We got a LOT of syrup from the next boil :)

I have to defend the helpers - they are actually better at firing, watching, pulling, etc... than I am, they have pretty much run every boil while I have run around cleaning, finishing, etc... But for every other boil, I turned everything on and opened the valves, and I failed to walk them through it properly. And of course, they'll be watching for this in the future.