Raised Flue Pan Too Sweet?

[wnybassman]

I have a small 18x60 rig with a raised flue. I feed it 8% concentrate and after boiling most of the season it starts to get kinda dark back there. Not sure of the sugar level, but is it possible to let the flue pan get too sweet?

[n8hutch]

As long as you're not having trouble getting the syrup off your rig w/o burning it you have no issues. Sounds like maybe your flue/sap pan could probably use a good cleaning, sometimes I'll clean mine 2 times in a season if the sugarsand is really heavy.

[Russell Lampron]

A sweet flue pan will do that. It's the nitre burning on the bottom of the flues and bacteria. I built a bubbler to deal with that issue back in 2013. It's worked great until this season. My flue pan darkened on the first boil and hasn't lightened since. I normally sweeten to 18% or so but on smaller runs have backed that down to 13% or so and the flue pan still stays dark. I sweetened to 14% from 2013 to 2019 and was making mostly Amber syrup with some Golden too.

You can try draining and cleaning the flue pan but at this point in the season starting over is probably not worth it. As long as your customers like Dark syrup continue boiling with it the way that it is.

[mainebackswoodssyrup]

We had some heavy niter in our last run so we drained the flue pan and gave it a rinse with hot water. We filtered the flue pan contents when we drained it. The pan really didn't look that bad but it couldn't hurt. Our syrup was still a medium but getting darker. I'd like to make a little more medium if we can so that's why we did it. May or may not work but we have plenty of customers who want dark as well. That's the last time we'll clean the flue pan until it's over.

[wnybassman]

Last night my syrup started to get a funky taste to it like it does near the end of every season, and always coincides with the darkest the flue pan gets during the season. I was just wondering if that had anything to do with it, or just the normal end of the season change.

A week ago I did drain and rinse out the flue pan. Had some sand, but not as much as the times I rinsed it last year. I am also VERY careful about bringing the contents of the flue pan to a good boil after flooding it during nightly shut down.

Gonna go out and give last nights syrup a good taste test this morning and make a season decision based on that.

[Russell Lampron]

If the funky taste is kind of bitter it's bacteria. Has your raw sap been cloudy lately?