2. Methods

2.1 Equipment List

No.	Equipment Name	Quantity
1.	Coffee Machine	1
2.	Retort Stand	1
3.	Thermometer	1
4.	Coffee Filter Bag	6
5.	Zip Lock Bag	6
6.	Grounded Coffee Beans (Varying Types)	6
7.	Electronic Balance	1
8.	Sieve	1
9.	Funnel	1
10.	Small jar	1
11.	Digital Refractometer	1
12.	Pipette	1
13.	Beaker	1

2.2 Diagrams of experimental setup

2.3 Procedures

Use sieve and funnel to filter the grounded coffee to ensure the grind size are the same Weigh 25g of grounded coffee beans using electronic balance Pour coffee beans into coffee machine with coffee filter paper Pour 250ml of deionized water into coffee machine Set up retort stand and thermometer, insert thermometer into coffee machine Heat water to 90 degrees celcius before allowing it to brew Measure concentration using TDS meter every 2 mins for the first 10 mins, every 5 mins from 10 mins to 1 hour.

2.4 Risk Assessment and Management

Risk	Assessment	Management
Hot water may cause scalding during accidental spillage	High	Wear protective mittens or use cloth when taking the beaker off the bunsen burner.
Boiling water may cause beaker to crack due to high temperatures, causing injuries	Medium	Make sure to control the temperature properly and not to place the test beaker in room temperature or warm water immediately after heating it.
Boiling water may overflow and scald	Medium	Only fill coffee machine to 250ml.
Wet hands may drop glass beaker causing it to crack or shatter.	Medium	Endure hands are dry before handling glass beaker and be careful.

2.5 Data analysis

Plot line graph & dot diagram to compare highest points of caffeine concentration of the 6 different types of coffee we have experimented on.