Rule of 86 still apply?

[reidridge]

I am boiling some sap for my neighbour and giving him back the syrup for a fee. I was wondering what equation I should use to figure out the amount of sap to syrup ratio. I know about the rule of 86 but this was for when syrup was at 65.5 brix. What ratio should I use for todays Brix

[bowhunter]

I'm 99% sure it's 87.1 now. Maybe someone else can confirm.

Dave

[jnmartin]

Here's an answer from another thread that might help.


I think I've figured it out. The problem is this: We want to know how much we have to boil down sap that contains P percent sugar in order to get standard maple syrup. Equivalently and a little more precisely, how many gallons, Gw, of water do we have to add to one gallon of standard maple syrup to make "sap" that condtains P percent sugar?

To begin with, we need some numbers:w

From my previous post, a gallon of standard grade A dark amber maple syrup weighs about 11.226 lbs and contains about 7.4781 lbs of sugar.

Also, one gallon of water at 60 degrees F weighs 8.337 lbs.

We want P percent of the total weight of liquid (the sap) we get by adding Gw gallons of water to one gallon of standard syrup to be 7.4781 (the weight of the sugar). So we set:

7.4781 = (P/100) * (11.226 + 8.337Gw)

Solving, we get Gw = 89.70/P - 1.347

Since we're adding the water to one gallon of syrup, the number of gallons of sap, Gsap, we have is Gsap = 89.70/P - 0.347

An easy to remember approximation would be Gsap = 90/P, that is, the number of gallons of sap that contains P percent sugar we have to boil down to produce one gallon of standard maple syrup is about 90/P.

[bowhunter]

Here's a quote from a post in April 2009 that references the 87 number. The information comes from Cornell Maple program and is consistent with the North American Maple Producers Manual.


"I emailed Steve Childs at the Cornell Maple Program. His repsonse makes perfect sense:

John, The discrepancy comes from the difference in weight of sugar and the weight of water. The Rule of 86 is calculated by dividing the weight of sugar in a gallon of 65.5 brix syrup (7.2115 pounds) by the weight of sugar in a gallon of sap at 1 brix (0.0836 pounds). The answer, 86.26 represents the number of gallons of 1 % sap that must be evaporated to produce syrup with a density of 65.5 Brix. The 65.5 brix was used in the old days when the rule was invented with the current syrup density of 66 it should be more like the rule of 87. In other words you are evaporating the lighter part of the volume and keeping the heavier part of the volume so more volume must be evaporated to get the end result than if the sugar and water were of equal weight. Hope this answers your question. Thank you. Steve Childs

Now I can sleep at night again..."

[Jmsmithy]

Using Rule of 87 did seem to work in my sugarbush...my sap been averaging 3*Brix on my Hydrometer and I am boiling at a ratio of about 30 (29 to be exact) to 1.... Going to pray to the Sugar Gods for 4* next season :lol:

[abbott]

What about the weight of the niter? You have three products when you make maple syrup... steam, syrup, and niter.

It seems to me that if I estimate using the rule of 90 it comes out about right. I figure that is reasonable considering the various losses in the process.