"Coffee Joulies" Review
by Randy Glass - Copyright 2012 - All rights reserved

"Joulies - Work Just As Advertised"

      It has been about eighteen months since I first heard about "Coffee Joulies," being originally brought to my attention by a post about a Kickstarter project to get them off the ground. I have anticipated getting my hands on a set for evaluation, and that time is now!

      If you are not familiar, Joulies are hollow, stainless steel, coffee bean shape capsules which are filled with a phase change material which melts at 140F. The theory is as follows: Dropping the Joulies into a hot liquid asnd they immediately absorb thermal energy changing the solid material inside them to a liquid. This transfer of energy raises the temperature of the Joulies and lowers the temperature of the liquid in the vessel. When the thermal energy of the Joulies exceeds that of the liquid (when they are slightly hotter than the liquid) they release their stored thermal energy keeping the liquid at a temperature fit for drinking for a longer period of time than would normally occur in that vessel.

      Coffee Joulies were invented by the two Daves who were neighbors and classmates in Pennington, New Jersey. Working from opposite coasts for 8 months, they conceived, engineered, prototyped, and hand-produced the first run of Coffee Joulies.
      On March 29, 2011 Coffee Joulies was launched as a project on Kickstarter. Originally hoping to raise $9500 to pay for half the cost of tooling, by the time the project ended on May 2 they had raised $306,944 earning them third place in the Kickstarter Hall of Fame and providing enough money to produce Joulies in the USA.
      They now work full time with Sherrill Manufacturing, located in the old Oneida factory in Sherrill, New York, and fulfilled the 8000 pre-orders placed through their Kickstarter page.
      The Kickstarter project helped the two Daves resurrect a closed factory, put some unemployed folks back to work, uses hydro-electric power to run the factory, and they use 85% recycled stainless steel. The Joulies are manufactured in an old silverware factory in Sherrill, New York. This is the exact same factory that used to make Oneida silverware before their manufacturing went overseas. They use machines, some a century old, that used to make silverware 24 hours a day but until they opened the factory, were sitting idle.
      Because the Joulies will be sitting in a beverage that will be consumed, material safety is their highest priority. They use 18/10 stainless steel, the same metal that is used in the highest quality silverware. The phase change material inside is a special blend of extremely pure plant-derived materials that are already used as ingredients in food. every single Joulie is tested for leaks using a helium leak tester, the same technology NASA uses to test parts used on the space shuttle.


      I took two identically-ugly (very used and very ugly) foam insulated cups with plain plastic snap tops (the tops are not insulated). I poured approximately 16 ounces of hot water into each cup (depth measured so that each contained the same volume of water). The initial temperature of the water after the filling of the mugs was around 185F. Into one of the cups I dropped four Joulies (one per four ounces as indicated in the instructions). The snap-on lids were put into place and the K thermocouple wires run down through the vent holes into the water. The logging meter was started at that time, set to record the temperature every six minutes. The setup was left on my coffee cart and off to work on this review I went. Hi-ho, hi-ho, as the seven height-challenged workers would sing (Doc, Bashful, Bluesy...).

      Here is the graph of the data I collected over a period of about 140 minutes (2.3 hours of data recording, to be exact). The drop in of the Joulies Immediately caused the temperature to begin to fall as indicated by the red line. It shows just how fast these things go to work! I have used the figures for "drinkable temperatures," from the Joulies website. "Too" anything is, of course, subjective, so take the ranges as indicated as just a point of reference - your palate may vary. The Joulies mug cooled to the "drinkable temperature" of 145F. in less than 6 minutes. The water mug took over 30 minutes to drop to that same temperature (difference in time indicated by the "A" on the graph).
      The period of time the liquid stayed within the range of "drinkable temperature" (from 155 down to 135) the Joulies maintained that temperature for around 54 minutes ("B"), and the unequipped mug maintained that temperature for 42 minutes ("C").
      While my test technique and equipment is not exactly lab quality (barely garage quality), the graph does indicate that the Joulies do what they are intended to do. What is that? Bring your beverage to a drinkable temperature sooner and keep it there longer.
      The better the insulation of the vessel the better Joulies work. In an insulated of vacuum bottle made to store hot beverages their performance is even better according to the Joulies website. Based on my observations from this test, I believe those claims to be accurate.

      Joulies are smooth in the hand and just feel good to hold. They are silky smooth, and although I was told they are each made from two pieces put together like the knife handles were, I could not see any evidence of a seam.
      If you carry a thermos of any hot beverage (it doesn't have to be coffee; it could be chicken soup), whether to work, commuting, or out fishing, dropping Joulies into that thermos will allow you to drink sooner and keep the beverage at a drinkable temperature longer, just as advertised. They displace approximately .75 ounces each so even all five in one thermos bottle will displace less than 4 ounces.
     You probably would not want to use them in an old-fashioned glass vacuum bottle, but in a stainless thermos they would work quite well, indeed. The better insulated the vessel is, the better Joulies will work. They will even work in a cup of hot coffee, dropping the temperature to a drinkable level quicker, but heat loss from the cup as well as into the atmosphere would lessen their effectiveness in prolonging the drinkable temperature.
      They are dishwasher safe and they say they will last a lifetime, just as any high-quality stainless steel silverware would. They are, of course, reusable.
      If you can't find them locally, they are available online, and even directly from the company. Available in a five pack with jute carrying and storage sack for $49.95 as seen at the top of the review, or in the Perfection Pack with a Joulies logo-branded, insulated "Thermos Sipp" travel tumbler in stainless steel with in its own jute sack for $79.95.
      Buy them. Use them. Don't like them? Send them back and get a refund! Two friends, with a great product, who stand behind what they sell. What more can be said?