Please order in multiples of 2 units. That is how they are packaged at the factory, with 46 evaporators packed per carton. Please note: the evaporator is sold without 65% Formic Acid. Click here for Formic Acid.
Take control of hive health effortlessly with the Nassenheider Professional Evaporator. This long-term evaporation system is designed for safe and effective treatment in beehives. Perfect for autumn (and spring) use, it utilizes a 65% formic acid (FA) solution for consistent evaporation over a 20-day period when using the No.2 wick. Beehives with high pest pressure can be brought into balance in a relatively short space of time. In areas with high re-infestation issues, it is recommended to do 2 treatments. For treatments in summer or during a honey flow, we recommend using Oxalic Acid Extended-release (OAE) strips.
Key Benefits:
- Cost-Effective Hive Care – A reliable, long-term solution that reduces expenses.
- Healthier Bees – Clients report reduced symptoms of chalkbrood and nosema after a 20-day FA treatment.
- Boosted Honey Yields – Stronger colonies mean better honey production.
- No Resistance – Nowhere in the world have pests grown resistance to these natural products – Formic Acid, Oxalic Acid or Thymol.
- Proven over Many Years – European beekeepers have been using natural products for over 40 years.
- No Residues – Formic Acid and Oxalic Acid leave zero residues in the comb.
- Less Sugar Feeding – Healthier bees naturally gather more food during the off-season.
- Simplified Safety – Easy-to-follow procedures minimize risks when handling formic acid. 65% FA is safer to handle than common off-the-shelf 84% FA.
Product Features:
- Complete Kit: Includes the evaporator, 250ml bottle, and three wick sizes for adjustable evaporation rates.
- No. 1 Wick: Very slow evaporation and suggested for use in nucleus colonies.
- No. 2 Wick: Ideal for single brood box colonies, evaporating 250ml of FA in approximately 18 days. Filling the bottle to the top (≈290ml) lasts around 20 days — about 14ml/day.
- No. 3 Wick: Recommended for double brood box colonies. One of our tests in Jan 2025 showed 250ml evaporation in 7 days (≈36ml/day).
- Versatile Design: The evaporator requires a 75mm spacer rim located directly above the brood box. 90mm top feeder rims or empty supers can also be used.
Extra 250ml Nassenheider bottle? Click Here.
Replacement Wick & Cloth Set? Click here.
Need a rim? Click Here.
Want mesh on the bottom of the rim? Shop Here
Evaporation Rates:
With 65% Formic Acid, it is recommended to evaporate between 9 and 22 millilitres per day per full-depth brood box. 22ml per day in one brood box is at a level where it is thought to disrupt pests under the cell cap. However, that high level of exposure is not necessary for good control. 14ml per day will eliminate virtually all phoretic pests (those on adult bees). Drone cells are capped for 14 days, so as long as there is continuous application for at least 15 days, effective control can be achieved.
Safety
Formic Acid liquid, and the gas from the liquid, can damage skin and eye tissue. It is very important that suitable protective clothing is worn. This is especially important when filling bottles from bulk containers. A respirator mask with face protection, nitrile gloves, PVC apron, and overalls should all be worn. Replacing empty bottles with full bottles in the field requires nitrile gloves as a minimum. Stand upwind when performing this procedure.
Field-Tested Results:
In a Featherston field trial, where autumn hive health management was historically challenging, the Nassenheider Evaporator delivered outstanding results, significantly improving colony strength and overall health. Read the full blog HERE.
Usage Tips:
- Assemble evaporator parts with the desired wick size.
- Spread the fleece cloth in the tray and secure it with the clips provided. Double up the cloth at one end so the post for the bottle clamp is not covered.
- Fit the bottle holder onto the post.
- In an outdoor location and with suitable protective clothing, fill the bottle with 250ml of FA and secure the lid for safe transportation.
- At the apiary site, place the tray on top of the brood nest.
- Remove lid from bottle and screw on the evaporator while the bottle is vertical.
- Check the screw connection for tightness to ensure safe operation.
- Place the bottle with evaporator into the bottle holder. See video for more info.
- Fit a 75mm rim to surround the evaporator. Fit hive mat and lid.
- For creative beekeepers: Cut old full-depth boxes into three rims and paraffin-dip them for sterilization.
- Top Tip: Extra bottles can be purchased separately here. Fill hundreds of bottles safely, then fit them to evaporators in the field as required. The beekeeper is exposed to minimal FA and only needs protective gloves — similar to handling Formic Pro pads.
- NB. If your beehive has a vented base, it is recommended to block the vents and leave the front entrance fully open for best results.
For more info and FAQ: Click here.
Why Choose Nassenheider?
Engineered for performance and safety, the Nassenheider Professional Evaporator is trusted by beekeepers to protect their hives effectively. With 46 units per carton, stock up for your apiary or share with fellow beekeepers. Order in multiples of 46 for the best value!
Use with 65% Formic Acid: Available here.