Tag Archives: Making Maple Syrup

Sugaring the modern way DIY Maple Syrup Reverse Osmosis (RO) system

A half dozen friends have asked me to share my Maple Sap Reverse Osmosis setup I use sugaring each spring to make delicious Maple Syrup. This year I decided to take some pictures and put a blog post together with relevant information for them. Originally I decided to see how cheaply I could put together a small batch process Reverse Osmosis setup for removing water from the Maple Sap I collected. In this version it has been upgraded with UV Sterilization. I am able to remove about 75% of the water with this set up, which translates to an enormous energy savings versus boiling. The best part about this system, is I set it up on a timer which I let run for the amount of time it takes to reach the maximum concentration of sugar.

I actually worked out the energy costs, and ROI last year but can’t find my notes on it. Here’s some quick calculations to show the value of this system. Sap is 98-97% water, you need to boil off most of that to get syrup which has to be 66+%. The latent Heat of boiling at atmospheric pressure for water is 8133 BTU/GAL if we assume 8.35 LB/GAL and take the steam table value rounded to 974 BTU/LB @ 212°F (100°C). Using this RO system saves about 6100 BTU per gallon of raw sap processed. If you use use propane, that’s equivalent to about 0.28 lbs of Propane burned if you have 100% efficiency (which does not happen in boiling but let’s be generous). Consider it can take up to 40 gallons of sap to make 1 gallon of syrup, you are saving 11.2 lbs of propane fuel which amounts to quite the $$ savings per gallon of syrup.

You can see a process flow diagram of my system outlined in the image below. It consists of an inlet that I move from either fresh sap tank to the filtered concentrate tank depending on if I’m adding more sap or trying to increase the sugar concentration. The inlet passes through a UV sterilization unit with a UVc bulb to kill any bacteria, yeast, etc. The UV sterilizer needs to be in front of the pump as the operating pressure of my system (~80-90psi) is higher than the UV sterilizer housing can handle (60psi max pressure). Priming is a bit of a pain with this set up, but once primed it works well.

Ensure you put your Reverse Osmosis Membrane in correctly. In my housing the membrane installs like this. Also check which of the ports is which in your system

The pump then pushes the liquid through a 1 micron filter column followed by a reverse osmosis membrane before returning the concentrated sap to the concentrate tank. Pure water is the waste in this system. I use it for my humidifiers in the house rather than dump it down the drain or outside. As it is purified water you can drink it, or use it however you would like. It seems a waste to dump it down the drain.

Process Flow Diagram of DIY Reverse Osmosis for batch process of Maple Sap to remove water before boiling it into Syrup

I used the following items from Amazon in building my system. In addition to this list of components I used you will need to source some 1/4″ water line, and 1/4″ push to connect fittings. In addition you will need some buckets, or containers to hold your sap. I keep my purified water for use in my humidifiers. You can run the pure water waste line directly to the drain or outside if you so choose.

Aquatec CDP 8800 high flow Pressure boost pump 8852-2J03-B423 100GPD – 200 GPD RO reverse osmosis booster pump 24VAC 1/4 and 3/8

Geekpure Ultraviolet Light Water Filter– UV Sterlizer Water Purifier (6W (0.5-1GPM)) https://www.amazon.com/gp/product/B07FPGCWQX/

Malida Water Pressure Gauge Stainless For Aquarium Meter 0-1.6MPa 0-220psi Reverse Osmosis System Pump With 1/4 https://www.amazon.com/gp/product/B0124FAV6Q/

Pentek 158117 1/4″ #10 Slim Line Clear Filter Housing https://www.amazon.com/gp/product/B003VT79VA/

Aquaboon 6-Pack of 1 Micron 10″ Sediment Water Filter Replacement Cartridge for Any Standard RO Unit | Whole House Sediment Filtration | Compatible with DuPont WFPFC5002, Pentek DGD series, RFC series https://www.amazon.com/gp/product/B01M0MIPUE/

1/4″High Pressure Needle Valve Thread Female Stainless Steel 316 J13W 160P https://www.amazon.com/gp/product/B00NBI3EEC/

Reverse Osmosis Membrane Housing with 1/4″ Quick-Connect Fittings https://www.amazon.com/gp/product/B00CCMNOSE/

HiKiNS Reverse Osmosis Membrane 100GPD for 5-Stage Home Drinking RO Water Filtration System 1-Pack https://www.amazon.com/gp/product/B0795R3NG3/

Pressure gauge on Maple Sugaring DIY RO system
Close the valve until you have a pressure in your system that is just under the maximum your membrane can handle. This will help push the water molecules through the membrane. You can see when your filter becomes plugged as the pressure drop between the two gauges will increase.

In operation, the input from the raw sap tank, and it all passes through the system at least once before entering into your concentrate storage tank. This filters out any solids on the first pass, and sterilizes the sap with the UV sterilizer. The one needle valve in the system is used for concentrate flow control. Decreasing the flow rate through the valve increases the pressure going into the filter and membrane. The increased pressure drives the water molecules through the membrane further concentrating your sugar solution. You want to run your system a bit below the safe operating pressure for your membrane or other weak link in your system. The concentrate is recycled through the system until pure water no longer drips out of the waste line. I find I can get to ~9-10% sugar content with this system.

DIY Reverse Osmosis for batch process of Maple Sap to remove water before boiling it into Syrup
Priming your system at the start of the season can be messy, especially if you forget to open the valve and bleed your pressure before disconnecting something. Make sure you use your setup somewhere a bit of water on the floor won’t hurt anything.

A quick note note on startup. RO membrane columns come with some preservative. Flush 10-15 gallons of fresh water through your system. Additionally, membranes operate differently at low temperature. So if like me your store your sap in an ice cave you build in a snow pile during the depth of winter, you want to let it come to 50Fish for processing, it will work much better than at 32-45F.

We are using water with electricity, make sure you use a GFCI on your system. My shop doesn’t have one, so I use a GFCI extension cord to ensure any shorting through the water trips the power. Safety is important when playing with AC line voltage. Be safe!

I hope this helps you with your own setup. Remember, you need to keep all these things clean. I wash and dry my system for storage, replacing my filter and column every season.

New Hampshire Maple syrup making – the 2012 experiment

Taps and Buckets on Maple Trees

Every since a childhood trip to a local sugar shack, I have wanted to make my own maple syrup.   A couple years ago I picked up some spiles (the taps that go in the tree).  This spring I decided I would finally make my own maple syrup.   I tapped four maples trees, purchased some plastic food grade buckets, and hung them up to collect maple sap.  I did a fair amount research in the form of reading the many how to publications, talking with some commercial producers at local sugar shacks, and watching a few educational programs on TV about maple syrup.  I had no idea how much sap my maple trees would yield nor how much work went into boiling the maple sap down into maple  syrup.  When you hear that it takes 40-50 gallons of sap to make 1 gallon of maple syrup you think, gee that’s a lot.  When you actually do it yourself you realize how colossal an amount of sap is required and that the energy and work required to produce 1 gallon of syrup makes it quite precious indeed.  This is not so much a how to post as a documentary post with notes for my next year.Maple Syrup sugaring on a wood stoveAs this was my first go at this, I used what resources I had available for my boiling down the maple sap into maple syrup.   I had a small wood cook stove that I thought would work well.   It took some figuring out how to burn the wood to keep the stove hot enough to keep the large 14″ diameter pot boiling.  I also borrowed a propane fired cook pot from my friends.   I ran both of these side by side.  I boiled off water at a rate of 2-3 Gal/hr with both running.  The propane was much easier to manage as I did not have to add wood every 30-45 minutes.  I made a heat shield later (post photos) that greatly increased the boiling efficiency of the propane unit.   Next year I think I will make a stainless steel evaporator pan that fits perfectly over the wood stove top.  This will give more surface area for evaporation and should decrease the time to boil down my sap into syrup

Finishing the maple syrup boiling process on the kitchen stove

After the bulk of the boiling was done outside I did the finishing and canning of my New Hampshire Maple Syrup in the kitchen.   I need to get a hydrometer and a better thermometer for next year.  I learned from my first batch of boiling that it is easy to over boil.   Over boiling results in sugar crystallizing and precipitating  from the syrup as “sugar sand” as your syrup cools.

I need an assistant for the canning process next year.   I will have to enlist the aid of a friend and bribe them with a jar or two of precious syrup.  It was quite hard to juggle everything during the canning process solo.   I used coffee filters in a little filter jig over each jar for filling.    Coffee filters have a very fine a pore size and blocked up rather quickly.  Coffee filters are cheap thankfully as I had to use a new filter for each jar I filled as the pores blocked up.  The smell of the boiling syrup fills the house with a wonderful warm aroma that lingers for the entire day.  I quite enjoyed the scent of maple syrup filling the house.


The first go around of boiling produced 25 oz of syrup from ~18 gallons of maple sap.   There were losses in the forms of minor spillage, sampling during process, filtering, etc.  I over boiled my first round and a large amount of sugar sand precipitated from it as it cooled.  My first round was capped with aluminum foil and put in the fridge for current use.  The second round of boiling I canned in small 4 and 8 oz jars for storage.  Before any friends and family ask, no there is none left for the asking this year.

first breakfast with home made New Hampshire Maple Syrup

This is my first meal I enjoyed with Zac’s New Hampshire Maple Syrup.  It was delicious.  The first run of syrup was very light and super sweet.  It was not strongly maple flavored but very enjoyable.  I have since enjoyed a breakfast that uses maple syrup on most mornings.   Food you grow or acquire yourself always tastes better and I can now say this holds doubly true for Maple Syrup you make yourself.

I’m certain I will do this again next year and suspect I will be a fair bit more serious about it.  I might build a small reverse osmosis unit using commonly available household cartridges to concentrate the sugars before boiling.  I will get some 55 gallon food grade barrels for sap storage as the 5 gallon pails are too small and you need too many of them.  I must come up with a better wood fired evaporator solution, either by building an arch from scratch or modifying my current wood cook-stove.