I want your opinions! Evaporator Options

[YoungFamilyFarm]

So... I am 99% positive I'm ordering an AA Metal shop evaporator in the next month. I want a 2x8 raised flue, but he has a 2x10 option as well. The flue pan is still 6', but the syrup pan goes from a 2x2 to a 2x4. What advantage would there be? Without more flu pan, would performance actually increase? I am concerned that the flue pan could actually be less efficient if you weren't firing as "close". Maybe that's wrong. The larger syrup pan seems like it may "even out" the draws though so that may be an advantage. Or is that wrong? I plan on 4-8% concentrate (R.O.) and hood/pre-heater. We'll be firing with hardwood which brings me to my next question. Standard 'natural' draft arch, or airtight with forced draft? My goal with a 2 ft set-up is efficiency, so does forced draft push more heat 'out the stack' or is the flue pan action worth the "loss". Will I be happy with natural draft? You guys are a wealth of knowledge (and opinions :) Let's hear em!

[smokeyamber]

Forced draft does burn more wood, but if it's AOF and AUF everyone here says it actually would use less. It would get more GPH for sure out of the arch too. If I were going that large I would also maximize the flue pan size. Some say with an RO you can go smaller on the arch... not sure how that would work on your 2x8 vs. 2x10, but I would think the 2x8 would do that many taps if they were on an RO.

For pans have you looked at Smokey Lake ? They are beautiful and he is awesome to work with. All his stuff is tig welded and really well built.

[WI Sugarpop]

We built our new arch for the 2014 season with AOF and AUF based on Maple Flat's design that I saw on a different thread. I have to say we are so glad we did that. This year we boiled down 2380 gallons of sap to 70 gallons of syrup using only 2 cords of wood. No RO either. No smoke and not much ash. It works great. Oh, and we doubled our gph from our previous arch that did not have forced air draft.

[Ed R]

I am assuming the fire box on the 2x10 is longer than the 2x8 so you can utilize longer wood like slabwood and pallets without cutting them down as much. I know its not as big of deal with a raised flue vs a drop but it would be easier to fire. I really like cutting my limbwood in longer lengths as well.

[motowbrowne]

I have a 2x10 with an 8' flue pan. It does about 65-70 gph natural draft, no hoods. Honestly, I'd see if they can do a 2x10 with a 7 or 8' flue pan or just get a 30"x8. I don't think you'll regret going to a little bigger rig.

[n8hutch]

I think boiling concentrate you might like the longer syrup pan, should be better as far as niter build up & less chance of making syrup in your flue Pan.

Disclaimer. I do not boil concentrate but I have some friends that do & they have said at times they wish that there syrup pan was bigger.

[Russell Lampron]

Having started out with natural draft and then adding a blower I saw the difference the forced draft makes. You want to get the airtight arch with forced draft. The increased heat and more consistent boil will make syrup faster you will actually use less wood. I would go with the 2x8 and concentrate to a higher percentage. If you want a 10' evaporator you would be better off to go wider as well.

[RFM]

A 2x8 with RO will handle 600 taps easy, but, if available, go with a crossflow syrup pan. I began with 12 taps in 2011, grew to 1100 taps in 2015. My CDL 2x2 reverse-flow syrup pan would nitre up on a big day at around 20 gallon of syrup. I changed to a crossflow pan and can now get around 30 gallons of syrup. If I were to buy another evaporator, I would go with a 30" x 8 , or 3x8 with crossflow syrup pan.

[mellondome]

Brian,
How many taps we talking? What for ro?

[YoungFamilyFarm]

Brian,
How many taps we talking? What for ro?

500 taps to start, and eventually we will be over 1000 I'm sure. I plan on getting a Ray Gingrich R.O. I figured on doing everything on a 2x6 and R.O., but once I saw the difference in pricing on AA equipment I can afford to go a bit bigger. I see you are in that neighborhood, are there many of Andy's evaporators running locally?

[maple flats]

I'd suggest the 2x10 with a 3 or 4' long syrup pan. My original 3x8 had a 6' flue pan and a 2' syrup pan. When I ordered my new pans, I got a 3x3 syrup and a 3x5 flue pan. This proved to be easier making syrup than the 3x2 syrup I had. I also got cross flow design with same side draw, another plus, but OSD design Sunrise has is even better. In that you are drawing from either of the 2 sections closer to the flue pan. There you will get a more consistant draw, on mine I draw from either the forward section or the back section, the back is better, but then every few hours I need to reverse the flow and then I'm drawing from the front section where it works OK but certainly not a well as the hotter rear section. If I were getting 2 more pans, I'd have them made using the OSD design the Sunrise uses, it just makes better sense.
As for length, a 2x10 will be more efficient than a 2x8. The longer you go, the more heat you can extract from the same wood.

[YoungFamilyFarm]

I'd suggest the 2x10 with a 3 or 4' long syrup pan. My original 3x8 had a 6' flue pan and a 2' syrup pan. When I ordered my new pans, I got a 3x3 syrup and a 3x5 flue pan. This proved to be easier making syrup than the 3x2 syrup I had. I also got cross flow design with same side draw, another plus, but OSD design Sunrise has is even better. In that you are drawing from either of the 2 sections closer to the flue pan. There you will get a more consistant draw, on mine I draw from either the forward section or the back section, the back is better, but then every few hours I need to reverse the flow and then I'm drawing from the front section where it works OK but certainly not a well as the hotter rear section. If I were getting 2 more pans, I'd have them made using the OSD design the Sunrise uses, it just makes better sense.
As for length, a 2x10 will be more efficient than a 2x8. The longer you go, the more heat you can extract from the same wood.

Thanks Dave! And thanks everyone. Keep em coming. I'm never afraid to learn from others. I don't want to be unhappy and then wish I asked more folks!

[mellondome]

There are a few complete evaps and lots of replacement pans locally. Your on the right path with a 2x? And an ro for that many taps. Will have to look at price sheet, but if a 30x ? Is almost same money.. it might be worth just a few extra bucks for the evap rate. I ran 1000 taps on my 2x6 this year... but was concentrating to 14-16 %. I have more taps to add.. so im looking to go to a 30x10.

Also, andy will work with you to make what you want... not just what is on the price sheet.

[Ryan Mahar]

Just to add to this, I just replied to another section in the forum, but we boil on a 2x6 revolution, steam away and RO 8-10%. 1200 taps on vacuum resulted in 415 gallons this year. Only one boil longer than 8 hours. Most were 6 hours boils processing around 1000 to 1500 gallons per boil. I know we can put 2000 taps through this evaporator and keep the boils around 10 hours or less, but that is pushing it for sure!..............however, we are expanding to well more than 2000 taps this coming year and so am selling my 2x6 set up. We have been advised to go with the 30 x10............... I love the 2x6, that is one very efficient rig....................