Hashtek Jar Experiment – Evaluation of Jar Seal Integrity through Measurement of VOC Loss


The objective of this experiment is to assess the seal integrity of various extract jars by measuring the evaporation loss of 99% Isopropyl alcohol over a period of time. Phase one will be conducted over a four-week duration at room temperature.

This protocol aims to provide a quantitative assessment of the effectiveness of jar seals in preventing evaporation of volatile organic compounds. 99% Isopropyl alcohol is being used in place of terpenes because its low boiling point and volatility make it an acceptable comparable.

Phase 1: Ambient Temperature and Pressure

In this experiment we will test 13 different types of jars, each model of jar will be tested in triplicate. A tare weight of each jar will be taken prior to being filled with a predetermined volume of alcohol. The volume of alcohol will be determined by taking 60% of manufacturers listed volume while taking into account the density of alcohol at 25C ((max vol.) x (0.6)) x(0.785g/ml). After a jar is filled with alcohol it will be sealed tightly with its respective lid. At this point gross and net weight will be recorded, which will serve as a baseline for future comparison. Once all jars have been weight they will be placed in a controlled environment with constant temperature and humidity. The jars will be removed from storage and have gross weights recorded at a recurring interval of 7 days for a total duration of four weeks.

Phase 2: Increased Temperature or Vacuum Environment

If the results from phase one are not significant, we will accelerate the experiment by increasing temperature and/or drawing vacuum on the jars in a controlled environment.

Foreword and Predictions

By conducting this experiment we hope to be able to reliably plot out the evaporative loss of alcohol over a period of four weeks and in turn gain valuable insights into the jar seal integrity for commonly used extract jars. The measurement of evaporation loss of alcohol over a four-week period will provide us with quantitative data to assess the performance of each jar model. This knowledge will help with making informed decisions about the storage and preservation of your solventless extracts.

It is my prediction that the mason jars will do the best.

Jars Being Tested

  • Miron 5mL
  • “Infinity 5mL” (Just a relabelled Miron jar as we learned)
  • Calyx v1 4mL
  • Calyx v2 4mL
  • Calyx v2 7mL
  • Pollen Gear 5mL
  • Amazon 3 mL
  • Pop Vac 5mL
  • Alchemy Jars 1oz
  • U-line 1oz
  • Mason Jar – 1 pint
  • Qube 5 mL
  • E-Bottle 9mL
  • 710 Labs (not for sale to the public, so we tested 3 used jars sent to us from Cali

Week 4: Final Results

As of Friday July 14th, 2023 the final results from the Hashtek Jar Experiment are in.

week 4 results

We believe the best way to display this information is via a bar graph (line graph was too confusing to look at):

Really puts into perspective how good that U-line jar is. It is also interesting to note that rate of evaporative loss is not equal in all the jars (evident by the fact we had a number of place changes over the 4 week testing period).

Top Three Results

Discussion of Phase 1 Results

Our thoughts on these results:

  • Miron Jars – are the clear winner from the small packaging jars. We emailed the company about the experiment and got a response along the lines of “we are not surprised”
  • Uline Jars – the gasket on these jars is notably thick. It appears to be white nitrile rubber, a material used on Hashtek machines in sealing applications. We knew these would do well, though the results are still impressive. Especially when compared to a mason jar, the industry standard for decarboxylation at pressure. Phase II testing at elevated temperatures will be interesting.
  • Calyx Jars – Surprisingly the v1 did much better than their v2 jars. The v2 jars come with a thin liner but the are seemingly identical otherwise. The percentage loss in the calyx v1 was very controlled allowing them to come back from 5th place to 3rd place in the small jar category.
  • Alchemy Jars – They had one outlier which dragged down their results. Speaking with their founder he explained this is due to differences in the supplied jar blanks (which are the same size 1oz jars that U-line uses). The Alchemy design adds insulation and light proofing to the best jar in this contest. Our recommendation to them was to build on their existing design but allow the U-line jar to use it’s original seal – don’t fix what is not broken. Super cool guys, would not be surprised to see an Alchemy V2 jar on the horizon.
  • PopVac – congrats to a fellow Canadian company on second place. They are new to the market and we recently co-sponsored a Heady Happenings sesh in Toronto with PopVac. Love to see a company that supports our industry. Doubt you would ever see Miron sponsoring a hash event!

Criticism of the Experiment

The guys at Calyx published a response to this experiment which is worth reading. Part of the scientific method is peer-review and we are glad there is a discussion regarding the methodology of this experiment. For example they brought up using actual terpenes for the test instead of isopropyl alcohol, which would be awesome for a study with deeper pockets than ours.

Hashtek Jar Experiment Results Timeline

Phase 1 of the Jar experiment was conducted over the following periods:

0June 16, 2023
7June 23, 2023
14June 30, 2023
21July 7, 2023
28July 14, 2023

Week 1 Results

Week 1 Results are in. During the early part of this experiment we learned that Infinity jars are just relabeled Miron jars. We decided to leave them in since we already had them. Interesting to note that there was identical results between the Miron and the Infinity jars when takin an average over 6 jars. We do feel this does really confirm the accuracy of the experiment.

It should be noted that there was an outlier with the Alchemy jars which significantly brought down their overall score.

Week 2 Results

Hashtek Jar Experiment - Week 2 results

Week 3 Results

Hashtek Jar Experiment Photos

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