The numbers
What each system yields per tap
The collection system sets your ceiling before the weather does. The figures below are per tap, per season, and come from the Producers Manual and the UVM and Cornell field trials behind it. They were measured in different woods and different years, so read them as ranges, not a race.
| System | Sap per tap | Syrup per tap | Where the number comes from |
|---|---|---|---|
| Buckets or bags (gravity) | ≈ 10 gal (5–15 typical) | ≈ 1 quart | Producers Manual, 2006 and 2022 editions; UMaine 5–15 gal; Ohio State 6–10 gal. Open-grown trees: 15–20 gal, up to 0.5 gal syrup (Cornell). |
| 5/16-inch gravity tubing | 5.8 gal (2014) · 11.25 gal (2015) | ≈ 0.17 gal | Cornell trials, 3 sites then 1 site. UVM: gravity tubing is often half or less of a pumped system. 2007 producer survey: tubing with no pump averaged 0.17 gal syrup per tap. |
| 3/16-inch natural vacuum | 10.3 gal (2014) · 18.2 gal (2015) | ≈ 0.24–0.42 gal at 2% sap | Cornell trials on sloped sites, 62–78% more than 5/16 gravity in the same years. The edge shrank to zero or below by year 3 in UVM's trial without fitting sanitation. |
| Pumped vacuum tubing | 15–25 gal or more | > 0.5 gal regularly | 2022 Producers Manual: a well-run system gives 100% or more over buckets (the 2006 edition said about 50%; Cornell says 50–150%). Each inch of mercury adds 5–7% sap. |
For planning, the 2022 Manual budgets 0.20 gallons of syrup per tap with traditional methods and 0.35 gallons or more with modern collection. The whole US industry, every method mixed, averaged 0.357 gallons per tap in 2026 (USDA NASS). Put your own tap count and method into the yield estimator.
What the sources actually say
Effort, gear and cost
Buckets win on simplicity. The Manual lists less maintenance (the whole system comes down each season), easy cleaning and sanitizing, fewer animal problems, and the pleasure of seeing what each tree gives. The cost is labor: collecting sap from buckets takes “considerably more labor” than a well-built tubing system, and sap should sit in a bucket no more than a few hours in warm weather. Cover every bucket; rain dilutes the sap and debris has to be filtered out.
Bags are the lightweight alternative to buckets, with the drawbacks in the FAQ below. Tubing costs money up front and thinking: installed cost was $7.50 to $20 per tap in the US as of 2022, and the Manual gives two lifespans for a system, every 15 to 20 years in one chapter and a current recommendation of 10 to 15 years in another, because aging tubing resists cleaning. Drops, fittings and laterals wear out before mainlines, and most producers replace droplines on a 3-year rotation.
- Tubing wants slope: 2% or more is optimal, and installs down to 0.5% are possible only with extreme care. Natural vacuum wants 5% or more.
- Droplines should be 30 inches or longer so tapholes can move around the tree over the years.
- A vacuum pump needs about 1 to 1.5 CFM per 100 taps; Cornell shows 12-volt pumps for 1 to 30 taps and 110-volt pumps that handle a few to 500.
- Storage: at least 1 gallon per tap per day of flow for buckets, 1.5 for gravity tubing, 2 for vacuum (Cornell calls 2 the safest estimate for anyone).
Old metal gear is a lead source
Often more than the system does
Sanitation changes the answer
Yield differences between systems can be smaller than the difference between a clean system and a dirty one. The 2022 Manual says bucket and bag yields “can almost double” with new or well-sanitized spouts, and that the closer a part is to the taphole, the more its cleanliness matters. On tubing, UVM's decade of trials found new spouts every year added 31% sap on average, a spout's age costs 3.7 times more yield than a dropline's, and a system with no sanitation at all settles at about half of a new system's yield within four to five years.
Before the season, wash buckets with hot water, sanitize with a 200 ppm bleach solution (0.55 ounces of 5% bleach per gallon of water) and rinse thoroughly with hot water. The full picture, including the sources that disagree about bleach, is in the sanitation guide.
Three sizes
What suits 5, 25 or 100 taps
- 1
5 taps: buckets or bags, and a shady spot for the sap
Five bucket taps on sugar maple should make about 5 quarts of syrup in an average year (five times the Manual's quart-a-tap figure). Use covered, food-grade containers: hardware-store 5-gallon buckets come in food-grade and non-food-grade versions, and 1-gallon milk jugs “quickly overfill” in a run. Small producers often run droplines from two or three taps into one bucket. Keep about a gallon of clean storage per tap and boil often; see how long sap keeps. - 2
25 taps: buckets still work, or one 3/16-inch lateral on a slope
UNH's backyard example sizes a 25-tap boil at 25 gallons of sap over 6 hours, so about 4.2 gallons an hour of evaporation. If the trees run downhill to a tank, 25 taps is about one 3/16-inch lateral: the 2022 Manual gives 10 to 25 taps per lateral in one place and 15 to 35 in another, on land sloped at least 3% (UVM Proctor) or 5% (the Manual). Plan 1.5 gallons of storage per tap for gravity tubing. How natural vacuum works → - 3
100 taps: tubing, a pump if the ground is flat, and a real evaporator
Cornell notes that past about 50 taps, small factory-made continuous-flow evaporators become the practical choice, and the Manual budgets a cord of dry hardwood per 75 to 100 taps on an efficient rig. A pump sized at 1 to 1.5 CFM per 100 taps (more on very flat terrain), 2 gallons of storage per tap, new spouts every year and droplines on a 3-year rotation are the standard package.
One honest caveat
No single controlled trial has compared buckets, 5/16-inch gravity, 3/16-inch natural vacuum and high vacuum in the same woods in the same year. The per-system yields above come from different trials and seasons, and the UVM figure that gravity tubing gives “half or less” of a pumped system is from a trade-press summary of their research. Treat the ranking as solid and the exact gaps as approximate, and let your own season log settle it for your trees.
