Reusing paper filter by placing metallic net filter in it

Question

First, what I do; then, the question.

I tend to brew coffee one cup at a time. To avoid waste, I only brew as much as I need, so I usually drink it all. In order to further reduce waste, I have tried metallic net filters instead of paper filters, but they tend to allow an ultra fine silt to pass through, the presence of which at the bottom of the cup is annoying if the plan is to drink all the coffee. So, I started doing this: first I place a paper filter in the coffee maker, to collect the ultra fine silt, which is actually very small in volume, and inside the paper filter I place the metallic net filter to collect the actual coffee grounds, which are 99% of the volume. Then, I brew my coffee. When it is time to make more coffee, I only remove and wash the metallic net filter; the paper filter stays in its place, and gets reused about five times before it has collected so much ultra-fine silt that it is time to replace it.

Now, the question.

Do you see anything seriously wrong with this technique? Does it perhaps have any side effects that I should be aware of? Would such a practice be considered yucky by some? (If it is, then this is a cultural issue that perhaps I should be aware of.) Obviously, the coffee smells and tastes fine to me, but I have to wonder whether noses and palates that are more sensitive than mine think otherwise.

I know, it says "we prefer questions that can be answered, not just discussed", so if you have something to say, please just state it without starting a long discussion about it! C-:=

Answer 1

Brewed coffee ages like milk. As soon as it is brewed its flavor begins to degrade and deteriorate, which is why it always tastes much better freshly brewed. While you may not necessarily taste the difference from one pot to the next, it has definitely changed your overall expectation of the flavor. The bouquet of coffee also is very complex, as is obvious from the fact that there is a distinct change in the scent from the time you grind to the time the brewing stops.

One flavor issue with reusing paper filters is that they tend to stop a large amount of the oils in the coffee from making it into the final product. This could be desirable, as many (myself included) prefer the taste of paper-filtered coffee that does not contain the compounds found in the crema (the thin layer of foam on top of espresso, Turkish or French-press coffee). These, which are often a combination of both sweet and bitter, are trapped by paper filters, but they will break down in the paper over multiple uses and wash into your coffee anyway, but not necessarily in the same form, which further changes the flavor profile.

If waste is a major concern, but you prefer paper-filtered coffee, you can make a compromise and use an Aeropress. These use filters that are only about 2 inches in total diameter, meaning less gets tossed with each brew. You could also look into filters made with recycled paper. It won't reduce the waste, but it will reduce the environmental impact somewhat.

Remember, though, that in the end paper filters are biodegradable and, if thrown away along with the grounds, can actually aid in creation of compost -- a good thing.

Answer 2

I also use a paper and mesh filter, but for a different reason. My drip machine has an attached grinder and came with a mesh filter. Paper filters leave a gap at the edge the generally results in ground going directly into the pot. I prefer paper filtered coffee, so I smash a paper filter outside the mesh filter and all my needs are met. I do however, replace the paper filter each pot I make.

Were I going to try and reuse the paper filter, I would most certainly wash it the same as the metallic mesh filter. The mud collected on the paper filter has the potential to both change the flavor of the next pot and also to grow mold and contaminate future pots. If nothing else I would say for hygienic reasons you should be washing the paper filter.

Answer 3

When you use two filters instead of one, first a courser filter (metal) and then a finer filter (paper), you believe you are extending the life of the finer filter, but in reality you are doing the opposite. By only letting the finer particles reach the paper, what you are doing is actually clogging the paper faster, because all those very fine particulates can find every tiny space unhindered by the deposition of larger particles, which would get in the way. A mix of different size particles should clog less and also be easier to rinse of. I suggest you do the following experiment: time every coffee extraction with your normal method (two filters) until you decide it is time to dispose of the paper filter (let's say 5 extractions). Then do the same number of extractions on just a paper filter having gently rinsed the filter between uses and compare the extraction times. If you get faster extractions on just paper, that means the filter is less clogged, and therefore, the coffee you are brewing is less affected by leftover old coffee. If not, then you are doing the right thing. You should do this over the course of as many days as it takes you to normally change filters so that the effects of "ageing" debris in the filter can happen.