Discussion: RO

That's awesome. We're not sugaring this year. It's been too crazy. Plus we still have plenty left from the last run 2 years ago. But I keep thinking RO is the next big step to add to streamline the process.

Did you get an off-the-shelf system or did you build it up from parts? And are you circulating indoors to keep the sap from freezing, or outdoors to keep it from getting too warm? (Or do you have a more direct means of maintaining desired temp?)

Totally homemade using very good instructions from a syrup maker. Cost was under $300.

I process the sap as I collect it and don't monitor temp. I do have a hand held refractometer (~$100) to measure sugar content (for wine making) and use that to measure the the sap and concentrate.

Usually I keep the sap outside so it will stay cold. If it partially freezes you can process the concentrated liquid sugar solution and toss the ice cube, as that is straight water ice. If it comes inside or gets warm outside, the sap can get guys growing in it who eventually devour the sugar and leave some interesting flavors.

Yeah that's why I asked. My understanding was that you want to keep the sap cold until time to boil. But as this guy notes, you can RO it faster if it's warmer. From what I'd read it sounded like you also don't want to risk freezing the RO membranes. So maybe the ideal setup is to have the tanks outside but the RO inside?

Thanks for the link to the description. I might give this a try later in the year if some free time magically appears. This setup is a bit different from the first one I read about. This one is a one-pass process with multiple membranes in series. The other one was a single membrane system that was set up to recirculate continuously. But that one was built with a small commercial RO unit. I like the looks of this setup much better for a small scale DIY system.

I have the RO setup in the kitchen. With the sap at 50-60 F last night I processed 5 gal in less than an hour. The sap won't go bad unless it's warm for several days. And yes, you don't want the membranes to freeze or they'll break down.

I'll email you a photo of the setup (don't have a site to post it at the moment).