Evaporation Rate with Concentrate

[BradWilson]

Morning All,

If you're up here in Northern VT I hope you're enjoying our little break. Our little 2x6 with a steam away will evaporate 50gph of raw sap (Leader helped us tune it up real nice). Now that we have the RO I'm wondering if the evaporation rate changes with higher concentrations. We obviously make more syrup faster but wasn't sure about the evap rate. Thanks again everyone. See ya out plowing.

[JoeJ]

The evaporation rate stays the same. Just more syrup per hour

[ecp]

I was always told the evaporation rate went down slightly with higher concentrate. Reason being it takes high temp to boil and there is less water to remove. Probably only a small difference though.

[maple flats]

I've never seen that discussed, in my head I figure evaporation unchanged, if it's slightly less evaporation, it's still well worth it in my book.

[ecp]

I've never seen that discussed, in my head I figure evaporation unchanged, if it's slightly less evaporation, it's still well worth it in my book. I agree it's still well worth it.

[DrTimPerkins]

As concentrate level increases, "evaporation rate" (the amount of water leaving the pans by evaporation) changes only very slightly -- not enough to notice without really close measurements.

What does change is "drawoff rate" (how much syrup is being removed from the pans) and "processing rate" (evaporation rate + drawoff rate).

"Feed rate" (amount of sap or concentrate entering the pans) also increases as concentration increases.

[mainebackswoodssyrup]

Interesting discussion, why would the feed rate not match the evaporation rate? Is it to do with the surging of drawoffs? Hence the advantage of modulating drawoffs?

[BradWilson]

As concentrate level increases, "evaporation rate" (the amount of water leaving the pans by evaporation) changes only very slightly -- not enough to notice without really close measurements.

What does change is "drawoff rate" (how much syrup is being removed from the pans) and "processing rate" (evaporation rate + drawoff rate).

"Feed rate" (amount of sap or concentrate entering the pans) also increases as concentration increases.

Thanks Doc! I guess I should have posted my question differently. My "feed rate" with raw sap was 50gph. And that's what I was curious about. Does feed rate change? I've changed my feed tank measurements from gallons to inches (time constraint and lack of flow meter) and I'm feeding about 7"/hr. Anyway, thanks all, Happy Easter!

[Super Sapper]

Interesting discussion, why would the feed rate not match the evaporation rate? Is it to do with the surging of draw offs? Hence the advantage of modulating draw offs?

Feed rate is the amount of sap or sweet that you are adding to the evaporator. This should equal your "evaporation" rate plus your "draw off" rate. If you feed 50 gph and draw off 1 gallon per hour your evaporation rate is 49 gph and your draw off rate is 1 gallon per hour to give you a processing rate of 50 gph. If you feed sweet from your RO and draw off 5 gallons per your and evaporation rate is 49 gph, your processing rate will be 54 gph.

[mainebackswoodssyrup]

Feed rate is the amount of sap or sweet that you are adding to the evaporator. This should equal your "evaporation" rate plus your "draw off" rate. If you feed 50 gph and draw off 1 gallon per hour your evaporation rate is 49 gph and your draw off rate is 1 gallon per hour to give you a processing rate of 50 gph. If you feed sweet from your RO and draw off 5 gallons per your and evaporation rate is 49 gph, your processing rate will be 54 gph.

10-4, that makes sense