Caffeine extraction from green coffee with supercritical CO2
TLDRIn this engaging experiment, the creator extracts purified caffeine from green coffee beans using supercritical CO2. Initially facing challenges with a paintball canister, they modify a supercritical drying chamber for better control. After moistening the beans to enhance CO2 penetration, they fill the chamber, heat it to induce supercritical conditions, and soak for hours. The result is a surprisingly black, caffeinated water, leading to a follow-up on extracting caffeine from the aqueous solution using methylene chloride, showcasing a process akin to industrial decaffeination.
Takeaways
- 📚 The script describes a DIY experiment to extract purified caffeine from green coffee beans using supercritical CO2.
- 🔨 The initial attempt using a paintball supply cannister and dry ice was unsuccessful due to lack of control over conditions.
- 🔧 The experimenter modified a supercritical drying chamber for aerogel production to create the extraction setup.
- 🔩 High-quality Teflon tape was used for sealing pipe fittings, with military-grade tape being preferred for its density and effectiveness.
- 💧 Water was placed at the bottom of the chamber to separate it from the coffee beans, which were placed above on an aluminum disc with holes.
- ☕️ Green coffee beans were moisturized before extraction to improve penetration by supercritical CO2, following patent suggestions.
- 🌡️ The chamber was heated to make the CO2 supercritical, and a pressure gauge was added for monitoring, exceeding the sight glass's working pressure limit.
- ⏱️ An 8-hour soak time was suggested by most patents, but the experimenter used an electric heating element overnight to maintain conditions.
- 🌡️ The extraction process involved maintaining a temperature of 50-60°C and a pressure of around 2,000 to 3,000 psi or slightly higher.
- 💦 After extraction, the water was drained and found to be extremely black, indicating the presence of extracted caffeine and other compounds.
- 🔬 The experimenter discovered caffeine crystals in the black water, confirming the success of the caffeine extraction process.
- 🚫 Despite the success, the experiment did not achieve the goal of extracting caffeine using only supercritical CO2 and water, as methylene chloride was needed for further extraction.
Q & A
What was the initial method attempted to extract caffeine from coffee beans?
-The initial method attempted was using a high-pressure paintball supply canister packed with dry ice and coffee beans, but it failed due to lack of control over the conditions inside the canister.
Why was the supercritical drying chamber modified for this experiment?
-The supercritical drying chamber was modified to better control the conditions and to accommodate the process of extracting caffeine from coffee beans using supercritical CO2.
What type of pipe fittings and tape were used in the modification of the chamber?
-Schedule 80 steel pipe fittings were used, along with high-density Teflon tape, which is referred to as military grade and is thicker and more dense than commercial grade tape.
How was the coffee bean preparation process different from the initial attempt?
-The coffee beans were moisturized before extraction, either by steaming or soaking in hot water, to make it easier for supercritical CO2 to penetrate and extract caffeine.
What was the purpose of using an aluminum disc with holes in the chamber?
-The aluminum disc with holes was used to support the coffee beans, preventing them from falling through while allowing the water to stay separate at the bottom of the chamber.
How much water was measured out for the experiment and what was its role?
-About 200 milliliters of water were measured out and poured into the chamber to create a separate compartment from the coffee beans, facilitating the extraction process.
What challenges were faced when loading the soaked coffee beans into the chamber?
-The soaked coffee beans swelled up and could not all fit into the chamber, leaving only about 3/4 of a pound able to be loaded due to space constraints.
How was the supercritical CO2 transferred into the chamber?
-The transfer was initially attempted through an inlet and outlet, but due to difficulties, the valves were closed, and the CO2 was heated gently in the supply cylinder, allowing liquid CO2 to be transferred to the chamber due to a pressure gradient.
What was the pressure and temperature range used in the experiment?
-The experiment used temperatures around 50-60 degrees Celsius and pressures around 2,000 to 3,000 psi, although some patents suggest higher values.
What was the outcome of the extraction process and how was it discovered?
-The water extracted was black like India ink, indicating a high caffeine content. This was confirmed by observing caffeine crystals forming after cooling the solution.
Why was methylene chloride used in the subsequent steps of the experiment?
-Methylene chloride was used for a hydrocarbon extraction to purify the caffeine from the aqueous solution, which contained many impurities and could not be filtered effectively.
What were the differences between this experiment and industrial decaffeination processes?
-In industrial processes, CO2 is pumped through the coffee beans and then washed to reintroduce relatively caffeine-free CO2, creating a constant gradient to decaffeinate the beans. In this experiment, caffeine leached into the water without such a gradient, leaving likely some caffeine remaining in the beans.
Outlines
🔬 Experimenting with Caffeine Extraction
The script describes an experiment involving the extraction of purified caffeine crystals from green coffee beans using supercritical CO2. Initially, the experimenter attempted extraction with a high-pressure paintball canister filled with dry ice and coffee beans, but this failed due to lack of control over the conditions. The experimenter then modified a supercritical drying chamber, adding more pipe fittings and Teflon tape for better sealing. The chamber was assembled with a water compartment at the bottom and an aluminum disc with holes to hold the coffee beans above the water. The green coffee beans were moistened to facilitate CO2 penetration and caffeine extraction. The chamber was filled with CO2 and heated to achieve supercritical conditions, despite facing difficulties with the packed beans and the pressure limits of the sight glass.
🌡️ Supercritical CO2 Extraction Process
The experimenter monitored the CO2 level using a sight glass while filling the chamber, aiming for a half-full level of liquid CO2. After sealing all valves, the chamber was heated to make the CO2 supercritical, reaching pressures exceeding the sight glass's limit. The chamber was wrapped in an electric heating element and fiberglass insulation to maintain the temperature and pressure overnight. The next day, after cooling, the experimenter extracted a black liquid, which was unexpectedly caffeinated. The liquid contained caffeine crystals, which were visible upon cooling. The experimenter noted the need for hydrocarbon extraction due to impurities, indicating a future video on the topic. The process was similar to industrial decaffeination, but without the continuous gradient to lower caffeine levels in the beans, suggesting that much caffeine remained in the beans after the experiment.
👋 Conclusion and Future Plans
The script concludes with the experimenter expressing excitement about the successful transfer of caffeine from the supercritical phase into the water, despite the need for methylene chloride to extract caffeine from the aqueous solution. The experimenter acknowledges that the goal of transitioning from green coffee to pure caffeine using only supercritical CO2 and water was not fully achieved but is optimistic about the results. They hint at future experiments and a video on caffeine extraction using methylene chloride, ending the script with a sign-off until the next video.
Mindmap
Keywords
💡Purified Caffeine
💡Supercritical CO2
💡Moisturizing
💡Steaming
💡Soaking
💡Patents
💡Decaffeination
💡Hydrocarbon Extraction
💡Methylene Chloride
💡Siphon Tube
💡Drain Valve
Highlights
Successfully extracted purified caffeine crystals from green coffee beans using supercritical CO2.
Initial attempt using a high-pressure paintball supply cannister and dry ice was unsuccessful due to lack of control over conditions.
Modified a supercritical drying chamber originally built for aerogel production to perform the caffeine extraction.
Utilized high-density Teflon tape for sealing large pipe fittings, which proved to be more effective than commercial grade.
Assembled the chamber with an additional six-inch pipe nipple on the top and bottom to accommodate water and coffee beans separately.
Machined an aluminum disc with holes to act as a screen, preventing coffee beans from mixing with water at the bottom of the chamber.
Moisturized green coffee beans before extraction as per patent suggestions to improve supercritical CO2 penetration.
Steamed and soaked coffee beans in hot water to prepare them for the extraction process.
Loaded soaked green coffee beans into the chamber, noting that they swelled and could not fit the entire pound.
Planned to have two fittings at the top for CO2 liquid transfer but faced issues due to the packed chamber.
Heated the CO2 supply cylinder to transfer liquid CO2 into the chamber by creating a pressure gradient.
Filled the chamber approximately half-full with liquid CO2, monitoring the level with a sight glass.
Heated the chamber to achieve supercritical conditions for CO2, exceeding the sight glass's working pressure limit.
Wrapped the chamber in an electric heating element and fiberglass insulation to maintain temperature and pressure overnight.
Extracted water after cooling the chamber, which was found to be extremely dark, indicating high caffeine content.
Tasted the extracted liquid, describing it as having a fresher, greener, herbal taste compared to regular coffee.
Observed caffeine crystals forming in the extracted liquid after cooling.
Had to resort to a hydrocarbon extraction due to impurities in the water, which will be the subject of a future video.
Compared the process to industrial decaffeination, noting differences in maintaining a caffeine gradient.
The experiment's goal was to transfer caffeine from green coffee beans to water using only supercritical CO2, which was achieved.
Plans for a future video on extracting caffeine from the aqueous solution using methylene chloride.
Transcripts
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