Week 6 – Midterm Oral Presentation and Filtration Method Experiment

Midterm Oral Presentation:

Filtration Method Experiment

This week, we explored the different filtration methods that we could use to extract coffee. One filtration method was using coffee filter paper, while the other was using paper towels. We decided that our goal was to determine if the usage of coffee filter paper or paper towels as a filtration method results in the most efficient coffee extraction.

We thought of three experimental questions that will support finding the answer to our goal:

  • What does the cost between coffee filter paper and paper towels say about the quality of them being used as a coffee extraction filtration method? Use experimental data to back up your answer.
  • How much more extractions can filter paper hold than paper towels?
  • Since paper towels differ from filter paper structurally, how do they affect the volume of the coffee extraction?

The experiment will work as follows: We will keep the particle size (fine), the temperature of water (40°C), and the mass of coffee beans (5 g) constant. We will have at least seven cups laid out and will brew coffee using coffee filter paper as the first trial and paper towels in replacement of the filter paper for the second trial. Each cup will represent a 30-second interval, so when the intervals are reached, the coffee extraction will brew over a new cup until all the cups are completed. We will measure the volume that each cup reached using a measuring cup as well as the conductivity using a probe once the samples are cooled down to room temperature. We will also measure the total volume of water used during the extraction process. We will use this data to construct volume vs time and concentration vs time graphs to compare which filtration method extracts the most coffee.

The variables we will study are the volumes of coffee reached, the amount of water used, and the concentration of coffee extract over time.

The only independent variable we are measuring is the flow rate from each filtration method. We will do two different filtration methods: one with coffee filter paper and one with paper towels. For each of these trials, we will proceed as normal with coffee brewing as we have for the past few weeks. The second trial will have a different filter (paper towel) inside the coffee filter cone but it should not hinder the normal coffee brewing procedure. We will fold the paper towel in a special way so that it can act as a coffee filter paper replacement. If needed, we can search online for instructions on how to make paper towels into coffee filter paper.

We expect paper towels to have less volume of coffee over time because paper towels are designed to absorb water, unlike coffee.  So, enough water would have to be poured over paper towels to first saturate them before flowing through with the coffee solubles.  So, water will spend more time picking up coffee solubles inside a paper towel used as a coffee filter.  Thus, we expect more concentrated coffee to pass through the paper towel.  So we predict the paper towel filter to have a lower flow rate but a higher concentration of coffee.

The general significance of this investigation is to explore the effects material properties have on coffee extraction.  Assuming we collected data on flow rate and concentration over time, we will use the results of this experiment to support a possible different, more effective filtration material in our specific design process (lycopene extraction).

More to be updated after the experiment has been conducted.

Leave a Reply