Benefits to gravity? Help me understand

[csk91]

Happy new year!
I have about 30 maple trees on my property and I live on the top of a hill so all of the trees are on some type of a downward slope. There is a 10-15 food drop in grade. Is there any benefit to trying to do a gravity set up for 2-4 trees in a run? Would there be a benefit to tapping a tree and having a 5-6 foot grade drop over 20 feet of 5/16 tubing before feeding into a storage container? Right now I just put leader check valve taps with 5/16 drops into 5 gallon buckets at the base of the tree. Just trying to determine if I could be “pulling” more sap out of my small property. Bought a new arch and nervous about feeding it.

[Sugarmaker]

Welcome,
Much, Much written about gravity and vacuum systems on 3/16 tubing systems. Your wont find much value on 5/16 for increased volume.
How big is your new arch? How many gallons is expected to boil per hour? How many taps do you have now?

Each tap in a good tree should produce approx 10 gallons of sap per season or about a quart of syrup. That is on just gravity buckets or 5/16 tubing/ The right 3/16 system in the right place might almost double that in theory.
Good luck with your season.
Regards,
Chris

[csk91]

Thanks for the reply. I have been reading but most of the information I am finding is about 20+ taps running in long 100 foot runs. I was wondering if there is a way to experiment with smaller runs using the tubing I already own. I have been using drops into buckets for 4 years. I have silver/swamp maples. I get about 3-5 gallons per week per tap when it’s running well. My sugar content is pretty low compared to a sugar maple.
I had a 16x30 flat pan on an insulated barrel stove. Going to a 20x48 Smokey lakes pan/arch. The pan is a flat pan divided into 3 channels so I can draw off as I go vs batch boiling. I think I’ll go from 5 gal per hour to 8-10.
In a good week I have over 100 gallons (so 10 hours of boiling minimum)... but on a down week I may only have 30 or 40 gallons... really looking to keep that low end number a lot higher or it is almost not worth the effort.

[therealtreehugger]

You said you live on the top of a hill - move your sugar making to the bottom of the hill, so you can have tubing go right into your storage tank. No more lugging buckets!!!! I didn't realize what a pain it was until I put up some tubing going directly to the sugar house!

[ronewold]

I'm very new to this, but I have done a ton of reading on doing natural vacuum tubing setup. 5/16 tubing isn't recommended for generating vacuum, 3/16 tubing is what people use. For every foot of drop from the tap to the tank, you can generate a theoretical 0.8 inches of vacuum, but you need to put a minimum of 4-5 taps on a single 3/16 line to get this to work. So with your 10-15 feet of drop, you could possibly generate 8-12 inches of vacuum, which would definitely help with sap production. If your trees are partway down the hill, some of this effect will be lost on them- and the trees at the bottom near the tank won't see any vacuum at all.
So if conditions are right at your place (majority of trees near the top and collection point near the bottom) and want to squeeze a little more production out of a limited number of trees, you might be able to get some benefit if you switch to 3/16.

[csk91]

Thank you. That is really helpful. I can get lower in grade if I move the collection point a few hundred feet away from the trees is there a downside to having a really long run after the last tree? Also would a switchback pattern or 180 degree turn as you zig zag the line create resistance in the flow defeating part of the gravity benifit? Does the run need to be in a general direction?

[buckeye gold]

That long run and fall from your last tree will actually help you create vacuum. Don't worry about turns and weaves. weaving in and out among threes helps keep tension on your lines. Just don't pinch it and your fine.

[mainebackswoodssyrup]

If you can collect at the bottom, run one 3/16" line from top to bottom with 5/16" drops and put all 30 taps on that one line. We have one bush that is 34 taps along a rock wall and we are trying 3/16" on it this year for the first time. Very similar to what you are describing. We have about 20' of drop in 500' so not max. vacuum but we should get some. Never know until you try. These trees are some of our best trees. If it doesn't work good, we'll replace the line for $50 next year with 5/16" tubing and some new tees (big deal!). Not going to bother with cleaning the line if it does work, will just replace the line after 3 seasons.

[maple flats]

With that drop you will do very well, having 25-30 taps on any 3/16 line in year 1. How you do in subsequent years depends on how well you clean the system, both soon after the season and then again mid-late fall. After year 1 there will be a "skin" layer left in the tubing which must be cleaned. If not removed that will have chunks scale off next year and will plug the fittings.
I have done well using 3/16 but I learned several tricks or steps to take. Soon after the last sap flow, wash the tubing using calcium chloride. It needs about 30 minute contact time to do a good job, then drain it out and flush well with potable water. (from the top) Then in mid to late fall, repeat. I also swap out every 3/16 fitting. I use 5/16 taps and drops, then all 3/16 laterals. Thus I use a new tap, tee and any connector in the line is changed for new. Mine are all also on good vacuum (26-27") and the connector before entering the mainline (a 3/16 x 5/16 connector) is changed. I've had good results doing this for 5 years now, but 2020 was down a little. 2016-2019 were all real good. This year I'll repeat the same.

[csk91]

Thanks since the run is so small and the tubing isn’t too expensive I think I could get away with just using it for one season. I was on bascom last night trying to figure out what I would need to buy in addition to the tubing. Got a little overwhelmed and backed off. Will go back today and see if I can figure it out. Might be too late for this season as I will be tapping in the next 3 weeks. We will see. Thanks for your help