Serial Extraction of Coffee and Tea

The following ingredients will be required:

• Ground coffee
• Boiling water

The following items will be required:

• Measuring spoons
• Measuring jug
• Five cups
• Filter paper
• Timer

Ensure that you read through all of the instructions before beginning the experiment to ensure that you understand exactly what will happen at each step.

Step one

Measure out two tablespoons of coffee into some filter paper and position the full filter paper into the bottom of the first cup, as shown in the figure below. Then place the four other cups in a row alongside the first, for the following fractions.

Step two

Boil the kettle and measure out 500 mL of boiling water into a measuring jug. You are going to need ~100 mL of water for each cup that you have. Not all the water will pass through the filter paper in the time allowed for the extractions, but it’s useful to have extra water in case you start to run out.

Step three

Set the timer to 30 seconds. As you start to pour the boiling water, slowly into the first cup, begin the timer. Stop pouring the water when the filter paper looks about half full – but keep topping it up, as it gets low. If you fill the filter paper up too much, you risk spilling the water as you try to transfer it between cups, which will ruin the experiment.

Step four

After the 30 seconds have passed, transfer the filter paper to the next cup, starting the timer again (for another 30 seconds) and ensuring to top up the water level in the filter paper when it looks like it is getting low. Continue until you have poured 100 mL of water into each cup. Look out for colour differences between the fractions.

Step five

Now you should taste each fraction of your coffee – remembering to leave enough to combine them at the end, so you can taste a complete cup of coffee – and you should record what each fraction tastes like. We have provided a table below of our results and a blank one in the downloads section for you to fill in. Make sure to take note of what kind of coffee you used.

Type of coffee: LavAzza Qualita Rossa Filter Coffee

After completing the table, mix each of your fractions into one cup and taste them all together. What does the resultant coffee mixture taste like?

For the tea drinkers among you, a further ‘tea extraction experiment’, blank results tables and the risk assessment can be located in the additional PDFs found at the bottom of the section. Remember to upload your results to our open Padlet (we have included some examples from a previous course to help inspire you) and/or on Twitter or Instagram hashtag #FLchemistry. Alternatively, you might like to explain your results using the comments section below. We are eager to see what you have been able to come up with!

Extraction competition

There will be a prize for the best photo/description posted on our Padlet site and/or on Twitter or Instagram by 9am on Monday 19 July (week 4). The prize will be given to the person whose photo/description, in the opinion of Andy, is the most striking, detailed, informative and well presented. We will advertise the name of the winner in week 4 (in the Comments below) who will be sent a paperback copy of Chemistry³ and a Chemistry@York fidget spinner. (This competition is being run by Andy / University of York and is not affiliated with FutureLearn and any personal details submitted by the learner will only be used for the purpose of sending the prize.)

We hope to get lots of interaction and that your extraction gives you satisfaction, and a positive reaction! Why not give it a go?