Does RO result in lighter syrup?

[tgormley358]

This will be my first season with RO as a backyard producer with 100+ taps. People are telling me they love my syrup, especially the darkest syrup i make. "really maple-y". I'm picking up a small RO tomorrow and plan to use it to remove 1/3 to 1/2 the water and reduce boil time. I've read many posts and articles saying experts find no difference in taste up to something like 10% sugar, and i'm planning to only go to 4-5%. But now i'm wondering, won't shorter boil times result in less dark syrup? Seems logical. When i explain (as a newbie, based on what i've heard) to people how darker syrup is made vs. lighter, i tell them later in the season the sugar content is lower so it takes longer to boil into syrup. So it struck me that shorter boil times with RO could result in syrup not as dark. Am i crazy?

Tom

[maple flats]

You will likely not see any difference. You should still get that great Dark syrup. I reduce mine from about 2% to between 10-12% sugar before it hits the evaporator, I see no change. If you only remove 1/2 of the water, you will only be taking 2% up to 4%

[tgormley358]

Thanks. but Oops, i just read the post just before mine and probably wouldn't have posted mine since it asks and answers mostly the same question i asked. Great minds think alike...that's a favorite expression.

[Russell Lampron]

RO will sometimes make lighter syrup and sometimes have the opposite effect. I concentrated from 14 to 18% and was making darker than dark syrup all season. I added a bubbler to my evaporator and now make mostly amber concentrating to the same percentages. It's all in how you process it and how fast.

As far as taste goes you can concentrate pretty high before it has a negative effect. On maple weekend I get a lot of compliments on how my syrup was the best that people had tasted and there's a lot of competition in my town.

[needmoremaples]

i made dark syrup last year with my 1200 gpd RO. syrup is usually darker because it sets longer. its usually darker late season because temps arent helping to keep it cool. thats bacteria at work. when you r.o. you concentrate the bacteria also and it can still make pretty dark syrup if you dont process it soon enough.

[VT_K9]

We ran a CDL Hobby 250 RO and a 2x6 Leader WSE evaporator. We found when we concentrated to 8-9% we were darker than if we stayed around 7-8%. I believe it is the type of evaporator in our case. Flavor was still great at all shades. We never made Fancy or Golden Delicate after using the RO.

We have a new evaporator and RO for this year. The challenge right now is getting the sugarhouse built.

Mike

[Daveg]

i made dark syrup last year with my 1200 gpd RO. syrup is usually darker because it sets longer. its usually darker late season because temps arent helping to keep it cool. thats bacteria at work. when you r.o. you concentrate the bacteria also and it can still make pretty dark syrup if you dont process it soon enough.

OOPs. it get's concentrated. Sorry.

[maple flats]

When you RO you remove all bacteria and viruses. That's why it is used for water purification worldwide.
Wrong, when you RO you concentrate the bacteria. The pure is the permeate we use for cleaning or we throw away, we keep the micro organisims and boil them. That is why unless you can refrigerate the concentrate to 30F or below, it should be boiled ASAP.

[DrTimPerkins]

Wrong, when you RO you concentrate the bacteria. The pure is the permeate we use for cleaning or we throw away, we keep the micro organisims and boil them. That is why unless you can refrigerate the concentrate to 30F or below, it should be boiled ASAP.

Although the microbial population "should" be knocked back considerably by filtering just prior to entering the RO (assuming you're using a good filtering system at this point--which you should be doing). Typically this is some type of cartridge filter, which generally give the best filtering results, but can clog more rapidly than other filtering types. This will keep your membranes cleaner and functioning better as well.

Dave is also correct that once sap has been concentrated, it should be either boiled soon (or refrigerated) to prevent spoilage, which will happen much faster than sap.

Those who concentrate via recirculation through an RO MAY end up with darker syrup due to the length of time sap/concentrate sits and the warming that occurs as sap/concentrate is processed in the RO system. Recirculation will result in higher warming and (typically) more time spent processing, thus more microbial growth, more sugar consumption by microbes, and more "inversion" of sucrose to fructose/glucose...thus darker syrup.

So, with all those variables factored in, depending on how you get there:

- RO can result in darker syrup
- RO can result in lighter syrup
- RO can have no effect on syrup color/flavor