Evaporation rates

[acorn roadster]

After many years of using buffet pans I'm looking to upgrade to a real maple syrup flat pan. Can you remind me, is the evaporation rate still going to be determined by surface area? I'll be boiling with wood, over blocks w/ fire bricks. I could hit 8-9 gallons/hr on 5 buffet pans (24x12x4). What size pan should I get to stay around 8-10 gallons an hour? I would like to get a smaller pan but 5-6 gallons an hour is slower than I'd like.

[Kbrooks80]

Yes. But drop flue or raised flue will increase surface area. I would at least go with a divided pan and add a float box so you can go continuous flow. this changes every thing.
Add an RO unit to increase your over all rate that you can process sap.

[berkshires]

It depends on the arch, on whether the sap is preheated, whether you have blown air or just natural draft, how high the sap level is in the pan, and how efficient you are at firing. All that being said, you should expect in the range of 1 to 2 gallons per hour per square foot from a divided flat pan on a good arch running pretty efficiently with dry wood. On my Mason 2x3 with a pre-heater and AUF last year I got between 11 and 12 GPH. But another user here - Aaron Stack, just down the road from me, gets 10+GPH on a 20x30 flat pan. That's 2.4 GPH! I dunno how he does it, but I guess it can be done with a flat pan!

Gabe

[Pdiamond]

Aaron probably runs that pan at no more than an inch and a half and keeps a close eye on it. He may also use a continuous feed system.

[82cabby]

Since you’re on blocks, flue pans and the like are probably out. If you can swing a 2’x4’ divided pan you could do well and that might fit the layout of the block arch you have set up, but it’s tough to pull off the fire. As the previous folks have said a 20 x 30 is a really convenient and workable size. If there is anyway to add a small blower your rate will increase.

Choose a pan size that would work with a conventional evaporator for when you want to upgrade that aspect of the operation.

Don’t discount the possibility of a small RO, like the RO bucket or the ones d.roseum describes on his web site. (https://m.youtube.com/@RoseumMapleSyrup). A small one will push at least 1/2 the water out of your sap which reduces your boiling time.

[Gord]

Kbrooks80 mentioned the RO. How do you calculate GPH between 2 of the same evaporators? One guy has 100 gallons of raw sap at 2%. Another has 100 gallons of concentrate at 8%. They both have the same evaporators. Are they both going to finish at the same time?
When you talk about GPH, are you talking about what you physically started with, regardless of sugar content?

[buckeye gold]

You don't say how many taps your running or if this is something your planning to do long term. If you have long term plans I suggest you go ahead and purchase a full evaporator set up. You will never regret it. I think it's worth it even if you have to finance one. Look at Maple trader https://www.facebook.com/groups/1833...03208123266941. There's a lot of used ones for reasonable on the market. It might take time, but you'll find one close enough to purchase and at an affordable price. Personally I'd buy new. All the manufacturers have hobby sizes. I modified an old half pint arch to accept a Smokey lakes hybrid pan with a float box and it was the best thing I ever done. If your making enough syrup to sell some you'll recover that cost in time....go for it, you'll be glad you did.

[82cabby]

Kbrooks80 mentioned the RO. How do you calculate GPH between 2 of the same evaporators? One guy has 100 gallons of raw sap at 2%. Another has 100 gallons of concentrate at 8%. They both have the same evaporators. Are they both going to finish at the same time?
When you talk about GPH, are you talking about what you physically started with, regardless of sugar content?

I missed kbrooks80’s comment, he’s spot on.

I think the above question is kind of apples and oranges. The person with 100 gallons of 8% started with something like 400 gallons of 2% and I would think you would take that into account. I guess for me the question is, overall, how many gallons of water do you remove from the sap in an hour Regardless of the method.

I think I have the math right so here goes: the guy with the 8% will net about 9 gallons of syrup so he needs to remove roughly 91 gallons of water. The guys with the 2% sap will net about 2.25 gallons of syrup so he needs to remove about 97.75 gallons of water. The guy with the 8% will finish first. I’m winging it here so someone check my math.

My trees generally run about 1.2% to 1.4% sugar so I have to remove a lot of water. I run two homemade ROs and that really reduces my boil time.

[Brian]

The thing is evaporation rate is the same except if the wood changes or the oil nozzel is altered or changed.The barmetric pressure is a big factor in evaporation also. The thing is like Mom adding salt to macaroni to make the water boil at a less temp because it breaks the surface tension, that being said, the water will boil at a lower temp. The depth of liquid is a big factor, the deeper it is the more btu's it takes to maintain the boil, the shallower it is the faster the evaporation happens. The ro just removes the water, it don't change the evaporation rate. I hope this makes sense

[Brian]

(I forgot this)The sugar in the sap changes the boiling point of the sap, the pure the water the higher the boiling point.