Maple Syrup, Maple Sap and Excess Water

Absolutely. Wiped film evaporators are ideal for this application.

I'm thinking, I'm thinking............would the evaporated water condense on the wall of the chamber and drip into a holding tank?

The water itself is in the air. It can be condensed in a separate chamber.

That's a good suggestion and one I've been seriously considering. I've seen the membranes used in filtering salt water.

Might I suggest that you keep any opened syrup in the freezer. There are certain moulds which can spoil the product very quickly.

Try adding ethanol to the sap or some other "seemingly" harmless solvent to distill the water out as an azeotrope (which will boil at a much lower temperature,for eg in the case of ethanol at 78 degC,thus saving your vitamins!). I don't know how thick the sap is,you could try using molecular sieves if it's not too sticky.

Hmmmm.....not bad .......not bad........got me thinking.

pasteurization occurs at above 127F {see FDA charts}

vacuum promotes evaporation at elevated temps

in sous vide cooking vegetables are usually cooked at 183F

there must be a temp where you notice a change in taste

obviously you will have to run a series of tests to find your balance point

the concept of adding a portion that has been processed at a higher temp adds another variable

good luck

Dehydration in vacuum - as DVader1000 said

Would you know of a schematic I can look at?

if you take 2 sealed container one foot in diameter and 2 feet high with a 3 inch tube between them. Place syrup in one side, and heat gently. The other side you cool. Then draw a vaccuum, 29" Mercury is enough. the warmed syrup will boil and the steam will condense on the other side.

In effect this is what a multiple effect evaporator is with a cascade of pressre stages,. It is used in sugar making.

http://acswebcontent.acs.org/landmarks/landmarks/sugar/

it can be used for syrup, but most places lack the volume to build these things

It appears by the consensus that vacuum chambers are the ticket. I think I'll start of with building a model and work my way upwards. Our facility is capable of RO'ing 4000 gal. of sap per day and the concentrate is cold stored for boiling off later. It is an intensive procedure and requires constant attention.

It appears by the consensus that vacuum chambers are the ticket.

Not correct. scale is the determining factor. Reverses osmosis is far more efficient in many cases. If you can use scrap wood of zero cost, then a wood fired boiler will cost less to run.

For large volume multiple effect evaporators will win.

I suspect a rural co-op might best use scrap wood.

There is also the compressed wood chip market. This has turned waste wood into a cash crop and many people use pressure augers to grind wood through a die into pellets. the heat of the process and the lignin in the wood act as a binder. These are bagged and sold in 50 pound bags to people with pellet furnaces (they also burn moldy corn, which cannot be eaten by man or beast.

http://www.google.ca/search?hl=en&q=%22pellet+making%22+%2Bstove&btnG=Search&meta=

Hi Rhabe........currently I'm using gravity as my RO pressure but haven't bothered to measure it. It is only to filter out about 70% of the water. The trick would be to find a membrane that can filter out water to exact proportion. Unfortunately my bank manager has convenient heart attacks everytime he sees me.

I like the idea of a double vacuum chamber. I'm currently using a double boiler to finish off the syrup (impossible to burn) but needs constant attention. Someone (sorry, forgot who exactly) mentioned using oil in the first boiler (I've been using water) and I suspect this is also an excellent idea.

RE: Someone (sorry, forgot who exactly) mentioned using oil in the first boiler (I've been using water) and I suspect this is also an excellent idea.

The problem with water in the first boiler is the difficulty of getting it above 100C, where it boils.

there are a few ways,

pressurization = risk of bang.

hot oil = risk of burning sysrup with bad control

hot salt water = less risk of burn, as long as you keep the salt out of the syrup.

since salt does not evaporate you can mark a level and replace water boiled off and as long as you keep the salt out of the syrup you are OK. You can also use glycerol to elevate the boiling point a few degrees.

I'm the last to reply to your suggestion because so far it makes a whole lot of sense and I can't shoot any holes through it. I never thought about using oil, glycerol or salt water but come to think of it it's a darn good idea!

How come I never thought of that!

I don't know much about raw syrup, but where I live, there are a lot of farms. When I first tried unpasteurized milk, I found it delicious. It had that 'Oomph' factor that the milk you find in the store didn't have. I find that I would feel the same way about raw sap. Seeing as it has so many nutrients before it is boiled down, I would definitely give it a taste.

If no one wants you to distribute maple syrup screaming 'sterility' concerns in your face, at least you can take comfort in knowing that you have something that no one else has!

I don't know much about maple syrup and the pasteurization process, but can't you just boil it just enough for the concoction to be considered free of bacteria and then can/bottle it?

Thanks Jaxi......you have the right idea. I also have tasted this unpasteurized milk and the cheese made from it. It is incomparable....and some say doable on a large scale considering all the sterility factors now involved in milking.

Unfortunately the same rules apply to milking trees.

Thanks everybody for the fine advice.

I'm in a position where the food agency allows me two temperature extremes........the first is 100'C + ...or boiling point, and the second is a max. 4'C chill point which facilitates a specific amount of allotable time for bacteria not to propagate. Unfortunately, warming is not an option.

I was thinking somewhere along the lines of using a type of tuning fork that vibrates at a high frequency that some cold water misting machines incorporate. I like the idea of using vacuum and am condsidering building a small model of a double flask....similar to a double boiler but in reverse.

http://www.google.ca/search?hl=en&q=%22reverse+osmosis%22+%2Bsap&btnG=Google+Search&meta=&aq=f&oq=

Thanks ...I use reverse osmosis and bacterial filters.

I cracked off the excess water after ro'ing by flash freezing using co2. The sugars separated from the water and the resulting taste and colour was quite good.

The colour is highly dependant on the run stage....ie..the first sap to run has the least amount of aldehydes and tannins and is a light amber colour. The colour becomes darker as sap run time goes on. There are two stages to boiling off....one is a preliminary stage where most of the water is boiled away and a second finishing stage where the final amount of water is slowly evaporated. Of course there are filtration stages inbetween for all except the final one.

In that case what you'll need are ultrasonic transducers . They have the advantage of killing bacteria by rupturing them open while simultaneously vaporizing the excess water . Before you use them though, it'll be best if you check with the transducer manufacturer if thickening maple syrup is a recommended use for them .

That's the track I'm aiming at. Didn't know but suspected if frequency high enough then bacteria will be killed off. Irradiation another prospect ... presently using 10,000W of UV light.

Hi Duckinthepobd,

UV is good but is penetrating into water only a few millimeter.

So let the stuff stream slowly (how long does the UV radiation take to kill the worst species?). Down-streaming a slightly inclined tray with a fluid thickness adjusted by the feeder and viscosity and inclination. This will do the best possible.

But:UV is generating ozone in the water and this will oxidise very fast everything that has some carbon or hydrogen atoms: the taste will be affected.

RHABE

Yes....that's exactly how it's done with a shallow tray in a sealed environment after filtration. So far we haven't detected any bacteria so this is just for added safety. I have given samples to test for mould and virus' and the amounts are too small to worry about.

To explain...all the trees are strung with poly tubing which is under vacuum to a central collecting point. In a perfect world no wind will blow and no branches will fall on the tubing. When this eventually does happen the largest concern becomes contamination. As long as the weather is cool I don't worry too much. If the temperature rises above 4'C I begin to worry. I also get very upset when some bear discovers a fountain of delicious and sweet nectar flowing from a hose he has learned to disconnect. I have also discovered it is impossible to fight with this creature so I hang some buckets for him and the deer to drink from....so far so good.

Guess what? News flash........ some guy just got busted in Toronto for purchasing ultrasonic transducers for shipment to Iran ostensibly for plutonium enrichment process.

I was about to make inquiries but think I'll wait a bit before being accused of attempting to make my maple syrup collapse into a critical mass state.

I grew up in Mennonite country.

Spigots in the trees, pails of sap, boiled in open pans over a wood fire.

Absolutely delicious!

We freeze the 4L bottles of syrup and they last for years.

Yep......that's how we did it also for many years. Knee deep in snow. Deer would drinking out of the buckets. 200 trees tapped. Open fire. It was a lot of fun.

Today it's 15k trees all vacuum hosed together, RO filtration, stainless steel vats...still use heavy horses though.

You're my kinda hillbilly! Apple Jack eh!

This thread is a great read, way more options in processing than I ever dreamed of... but there's more...

Check out this article by Favreau et al from McGill University, on microwave processing of maple sap to syrup. Can do it.

Also, for those who recommended filtration, Pouliot et al from Laval have used ultrafiltration to produce a clear "cold sterilized" sap. If you want to dispute the temperature restrictions with the CFIA, a copy of this research might be useful.

I went looking, and found surprisingly little literature on medicinal constituents unique to maple syrup, but the Japanese and Chinese are starting to publish research on Maple leaf and bark constituents: some of their Maple species are used in traditional medicine and are reported to have anti-cancer effects.

"Quebrachitol", of the inositols, is mentioned in a 1967 study by Stinson et al, where it's said to be more abundant in maple sap than all monosaccharides combined. Maybe an important nutrient for neural messaging systems, it looks as though there's research ongoing, so we may see some news on this in the near future. Eyemark inositol.

Not that you will ever need medicinal markets to sell maple syrup!! But I take perverse enjoyment from the thought that lavish treats are.. good for me

wow....just added all to bookmarks. Ultrafiltration good but membranes are cost prohibitive.

Had heard of research from U of Guelph regarding calcium type found in sap. Apparently high in strontium and anion binders. Possibly good for osteo patients?

Good call. Korean traditional medicine calls it "bone-benefit-water", and research found it ameliorates low bone density in a mouse model.

UF isn't really suitable for highly concentrated maple syrup anyway . The viscosity is too high . To know more about ultrasonic transducers and their suitability for this purpose, you can contact Mr. Scott Morgan at smorgan@humidifirst.com . His company manufactures transducers for vaporizing water, so he can advice you on this .

Perhaps some of people don't know the amount of energy it takes to make M.S. To put it into perspective the concentration ratio is 40:1. Therefore it takes 40 litres of Sap to make 1 litre of Syrup. Now you can understand why many large scale producers go to R.O. This was a good year for syrup as around here they were averaging 1.25~1.5 litres per tree.

Regarding the Sap, it has the consistency and clarity of water, as well the taste is similar to water just with a very slight sweetness although hardly noticeable.

Hi PTT.......this has been the best year for syrup since 25 yrs. We were averaging 38/1 ratio as opposed to the norm 40/1....and yep, you're absolutely right about energy (mine and everybody else' who are scheduled for intensive chiropractic services) not to mention the boil off.

Been away on holidays, so didn't see this thread.

Reminds me of one of the challenges some months back to get water out of an alcohol mixture.

If you are to filter the sap before final boil down (and flavour concentration) then what about adding "plaster of paris" to bond with some of the water molecules?

This is easily filtered off, and can be readily recycled by heating again to drive off the water content.

(The idea actually came from someone else, but I was so impressed that it's stuck in my memory.)

OK.......this is so far out in left field that I'm now tempted to try it. If there are no residual noxious chemicals, flavours or ph disturbances the idea must pass the food inspection authorities. Do you know of any research or documentation that proposes this?

The formation of hydrates is a well known procedure to remove water from otherwise hard to separate mixtures, drying ethanol, for example, is one of the common ones in use.

It is very likely there will be a strange taste and the matrix of hydrated plaster will entrain a large amount of the syrup as well as water since you are concentrating 40:1 you will need so much plaster to deal with 40 pounds of syrup that the one pound of syrup left will just make a poor glue as the end result.

With Ethanol, you distill to the aeziotrope of ~95% and then use an anhydride to strip the lst 5%. The amount left on the hydrate crystals is small in comparison.

Plaster of Paris is non-toxic. In fact, it's used as a coagulant in tofu production.

Yes, Gypsum, I see it in the recipes.

A small amount is used, it seems to be flavor free

http://www.soymilkquick.com/makingtofu.php

http://en.wikipedia.org/wiki/Tofu

I think there is too much water in maple syrup for it to work.

It might work if it's concentrated enough.

These anhydrides can only be used for removing small amounts of water. Syrup is 60-70% water, so it is totally impractical to use it at any stage, like going from 20% to 30% would take on a 1000 pound batch(10 pounds of pure sugar) of say that you boil from 1% to 20% = 50 pounds of 20% sap you need to take to 30% or 33.3 pounds of syrup with enough plaster to absorb 16.7 pounds of water?

I think you would have a sweet lump of sticky plaster

Yep! And they thought adding Melamine to baby formula would be fine too!

I would consider addition of any foreign material in process to the actual product to be "science experiments" only. Introduction of R.O. was a great idea and IMO the best and perhaps the only way to improve in the production of M.S. in comparison to the traditional method of full evaporation from start to finish. BTW we had pancakes last night with Syrup made on our farm the traditional way (we yielded 110 litres from 75 taps on 45 trees) and it was grrreeaatt!

Nice!!

My favourite has always been the second run. It's darker but has (in my opinion) the most flavour.

The co-op we're composed of uses approx. 50 face cords of hardwood to boil off the remaining water AFTER filtration. Of course the idiot who built the boiler (me) is the only one capable of running the damn thing which is why, after ten years, I'm looking for an alternate means of syrup recovery...though if retrospect is 20/20 I'm probably going to get stuck with running the damn thing after building it.

Seems the idea has hit the "thought" button for a few readers.

I had imagined using only enough to absorb the first 10% of water rather than all of it. This would mean less water to boil off from the remaining syrup.

The energy needs would not change though as to "re-constitute" the plaster for re-use still requires heat.

I imagine though the set-up should be using very shallow pans over the heat, a little like jam making so that evaporation is enhanced. High draft over the pans would help drive away the water vapour and provide a lower partial pressure for subsequent evaporation.

Give Maxwell's demon a pair of molecular tongs and put him to work.

let him have 1% of the water as his fee...

hello duckinthepond,

i was going to make the same suggestion as post number 17, but he beat me to it.

i do have something else that might help your process though. i found out that bacteria can not survive high magnetism. i found this out researching diesel fuel. there is a product out there, i believe it is called "debug". it is a cylinder that has opposed magnetic disks inside. you pump the diesel thru it and it kills the bacteria. these are not electro-magnets, just magnets. the cylinder is designed to go inline. it has threads at each end. wasn't that expensive either. you just pump the fluid thru it. you could put one on the output line wherever you are pumping.

joe