Calculating sugar content percentage

[DaveB]

I thought this sub-forum would be the best place to post this but I'm wondering what is the easiest way to calculate what the sugar content would be if I mixed RO concentrate with regular sap. I know that if I have 20 gallons of sap at 8% sugar content and mix it with 80 gallons of sap with a 2% sugar content that I'll wind with 100 gallons of sap with a sugar content somewhere between 2 and 8%. I'm racking my brain trying to remember my chemistry classes to figure that out but I'm wondering if someone can help me remember. Thanks!

[bowhunter]

This is not precise, but it's close enough. Multiply the fraction of 8% by 8% and add it to the fraction of 2% multiplied by 2%. Here's how it works:

100 gallons of sap total so: 8% x 0.2 = 1.6%, 2% x 0.8 = 1.6% therefore the blend = 1.6% + 1.6% = 3.2%

[KGodshall]

There is an exact formula........ and it alludes me at the moment......... however:

20 gallons of sap @ 8% = 1.6 gallons sugar
100 gallons of sap @ 2%= 2 gallons of sugar

1.6+ 2 = 3.6 divided by the total gallons (100+20=120) yields 3%........

Where did I go wrong? (I'm sure I did....... darn high school algebra.......)

[KGodshall]

Sorry a bit adult ADD here.......

So: 20 gallons x 8% + 100 gallons x 2% = 120 gallons x "x%"

1.60+2.00=120x
3.60=120x
.03=x

x= 3% sugar content in 120 gallons.

Yes?

[bowhunter]

You have 100 gallons total. 20 gallons at 8% and 80 gallons at 2%. The 8% is 0.2 of the 100 gallons and the 2% is 0.8 of the 100 gallons. Multiply 0.2 times 8% which equals 1.6%. Multiply 0.8 times 2% which equals 1.6%. Add 1.6% to 1.6% and it equals 3.2%. This doesn't account for the slight difference in densities, but it close enough for your purposes.

[KGodshall]

Oh sorry, I thought there was 100 gallons @ 2%....... (multiple choice would have helped here.......)

So:
20(.08)+80(.02)=100(x)
1.6+1.6=100x
3.2=100x
.032=x or 3.2%

Do I get a partial credit?

[DaveB]

I'm glad that I wasn't the only one reaching for that one but that looks like what I was looking for. Thanks guys!

[David S]

Hello Members,

My question relates to the previous comments on this thread regarding final sugar % of mixing two different sugar densities, but rather the amount of evaporated water, in litres/US gallons/UK gallons, to be removed to arrive at a spec % of sugar content.

The rule of 86 which I have seen reference many places, somehow doesn't seem to work i.e. sap at 2 % therefore:
86 /2 - 1 = 42 US gallons of sap evaporated/removed to achieve 66 % - maple syrup.

For instance: How many litres/US gallons of water are required to be removed from a 100 litres of sap starting at 3 % content to achieve a content of 16 % ? How many litres removed from 100 litres of sap to go from a start of 1.5 % to 10 %?

I realize that there are density changes involved regarding mole(s)/chemistry, but it is probably only fractional for my purposes.

Appreciate any help,

David S