<p>Here is what I found:</p>

<ul>
<li>Trying to tear out a proper filter is difficult. Filters do resist to boiling-water temperature.</li>
<li>Trying to tear out a proper filter <em>along the seam</em> is quite easy.</li>
</ul>

<p>So, by folding the filter on the seam, it seems we kind of hide the seam from direct contact with hot water. The seam glue is <em>not</em> weak these days, but this way there is no risk of tearing (e.g. if there is a defect in the seam), and the surface area inside the filter is also more uniform---the filter stands well in place.</p>

<p>There is a seam in the first place, because it is easy to manufacture fold-able filters this way (I am looking for a citation here).</p>

CC BY-SA 3.0
2016-01-27T15:45:18.193Z
Well, I answer my question in the end. I select this as the answer, after trying to understand *why* we end up folding filters.
Eric Platon
CC BY-SA 3.0
2015-02-10T00:29:34.480Z
2015-02-10T00:29:34.480Z
Eric Platon
<p>I did a little bit of research at the site of inventor of the coffee filter. It's Melitta from Germany. In the <a href="http://www.melitta.de/de/FAQ-229.html" rel="nofollow noreferrer">german FAQ</a> I found the following:</p>
<blockquote>
<p><strong>Warum falte ich Filterpapier vor dem Einlegen um?</strong></p>
<p>Damit die Kaffeezubereitung optimal funktioniert, muss das
Filterpapier genau in die Form des Filters gebracht werden. Dies
geschieht, indem Sie die beiden geprägten Ränder umfalten. Das
Filterpapier schmiegt sich dadurch an den Rand des Filters an und
sitzt tief im Filtereinsatz. Durch diese gute Passform kann sich das
Filterpapier während des Brühvorgangs nicht einklappen</p>
</blockquote>
<p>In English:</p>
<blockquote>
<p><strong>Why I fold the coffee filter?</strong></p>
<p>In order for the coffee preparation to work optimally, the filter paper must be brought exactly into the shape of the filter. This is done by folding over the two embossed edges. This causes the filter paper to nestle against the edge of the filter and sit deep in the filter insert. This good fit prevents the filter paper from folding in during the brewing process</p>
</blockquote>
<p>Additional fact: The coffee filter was not invented by Melitta the company, but by <a href="https://en.wikipedia.org/wiki/Melitta_Bentz" rel="nofollow noreferrer">Melitta Bentz</a>.</p>
<hr />
<p>Note: The translation might have some mistakes as my English is really not the best. Please consider improving it through (suggested) edits.</p>

CC BY-SA 3.0
2016-01-27T15:43:45.500Z
Thank you for your answer. I really would like the selected response to tell *why* folding matters. For this reason I choose another one as the answer, and surprisingly, mine...
Eric Platon
CC BY-SA 4.0
2015-02-12T08:24:08.037Z
2024-07-22T14:48:03.743Z
2024-07-22T14:48:03.743Z
Tim
<p>Good Morning coffee drinkers !</p>

<p>I am now getting on for 70 years old  and I remember when my mother in Norfolk UK bought her first ground coffee filter machine. She used "Melitta" filters and told me to always fold the two seams. I have never forgotten this advice and along with a lot of knowledge passed on over the years I continue to do this. I settled in France around 30 years ago and have never noticed any one folding the edges over here  -  even my french wife has never accepted that it is necessary. However, she has, from time to time had the filter collapse when she has been responsible for preparing the coffee.....</p>

<p>SO  -  the reasons for doing this are to me, at any rate fairly clear and I agree with the reasoning of both the Melitta company &amp; Eric Platon.</p>

CC BY-SA 3.0
2017-02-01T08:43:34.773Z
2017-02-01T08:43:34.773Z
Bob  Sar
<p>Standard and V60 paper filters require we fold the border before spreading them for dripping.</p>

<p>I believe this is just because of their manufacturing process. But would there be any other reason?</p>

<p>Folding that border makes the surface uneven in the end, and it can sometimes be harder to control the water flow.</p>

<p><img src="https://i.sstatic.net/R6Tms.jpg" alt="Folded border on a V60 filter"></p>

CC BY-SA 3.0
2015-02-10T20:52:30.043Z
Which part are you folding? I'm with @AlexB -- I have never found a reason to fold V60 filters.  On the other hand, folding #2 filters is necessary so that the seams don't interfere with the filter physically fitting in the cone (which, for #2 dripper, isn't precisely a cone, because it has a flat/straight/distended bit on the bottom), but this isn't an issue with the round-holed-bottom nature of the V60 dripper with the (truly) conical V60 filter.
hoc_age
CC BY-SA 3.0
2015-02-11T13:16:58.047Z
Just added a picture. Without folding the edge, the filter does not stand nicely in its support. I prefer to fold it to have a nicely even surface inside.
Eric Platon
CC BY-SA 3.0
2015-02-11T16:00:39.720Z
Now I see; good clarification; folding is for mechanical convenience/necessity. But doesn't the seam just lay down flat when you put it in? The filters I use are more like [these Chemex filters](http://www.chemexcoffeemaker.com/filter-folding-101); they're folded from a flat sheet, so they don't need additional folding, unless the cone is of a different "slope" than the filter. I'd suggest expanding to include Melitta-style cones ("#2" or so). Or perhaps I'll post a pic when I have a moment.
hoc_age
CC BY-SA 3.0
2015-02-12T22:34:29.150Z
@hoc_age the filter somewhat lays down flat after getting loaded with the ground coffee, but the position it takes can be a bit random. Folding the edge first is more predictable.
Eric Platon
CC BY-SA 3.0
2015-02-12T22:37:26.087Z
Thanks for mentioning the Chemex. You explain exactly why I did not include them! The flat sheet that we wrap into a cone does not need folding, indeed---there is no seam. And that's perhaps what seam folding tries to achieve: A homogeneous surface inside the filter, which is natural with the Chemex filter you mention.
Eric Platon
CC BY-SA 3.0
2015-02-04T10:19:03.260Z
I googled a picture of v60. they appear to be pretty standard, i dont recall ever "folding the borders" on them. perhaps it's unique to the size/shape of your machine? Can you elaborate on "folding the border"?
Alex
CC BY-SA 3.0
2015-02-04T13:28:36.307Z
I just use Hario's V60 filters. They have a seam on the side, as standard filters. It seems pretty common to fold the border with the seam before dripping. Thinking on how making that clearer in the question... Does it make sense?
Eric Platon
<filter><drip-brew>
Why do we need to fold the border of filters?
Eric Platon
# Why do we need to fold the border of filters?

(Asked by: username_0 on 2015-01-28)

Standard and V60 paper filters require we fold the border before spreading them for dripping.

I believe this is just because of their manufacturing process. But would there be any other reason?

Folding that border makes the surface uneven in the end, and it can sometimes be harder to control the water flow.

![Folded border on a V60 filter](https://i.sstatic.net/R6Tms.jpg)

**Tags:** filter, drip-brew

> **Comments:**
> **username_2**: I googled a picture of v60. they appear to be pretty standard, i dont recall ever "folding the borders" on them. perhaps it's unique to the size/shape of your machine? Can you elaborate on "folding the border"?  
> **username_0**: I just use Hario's V60 filters. They have a seam on the side, as standard filters. It seems pretty common to fold the border with the seam before dripping. Thinking on how making that clearer in the question... Does it make sense?  
> **username_1**: Which part are you folding? I'm with @username_2B -- I have never found a reason to fold V60 filters.  On the other hand, folding #2 filters is necessary so that the seams don't interfere with the filter physically fitting in the cone (which, for #2 dripper, isn't precisely a cone, because it has a flat/straight/distended bit on the bottom), but this isn't an issue with the round-holed-bottom nature of the V60 dripper with the (truly) conical V60 filter.  
> **username_0**: Just added a picture. Without folding the edge, the filter does not stand nicely in its support. I prefer to fold it to have a nicely even surface inside.  
> **username_1**: Now I see; good clarification; folding is for mechanical convenience/necessity. But doesn't the seam just lay down flat when you put it in? The filters I use are more like [these Chemex filters](http://www.chemexcoffeemaker.com/filter-folding-101); they're folded from a flat sheet, so they don't need additional folding, unless the cone is of a different "slope" than the filter. I'd suggest expanding to include Melitta-style cones ("#2" or so). Or perhaps I'll post a pic when I have a moment.  
> **username_0**: @username_1 the filter somewhat lays down flat after getting loaded with the ground coffee, but the position it takes can be a bit random. Folding the edge first is more predictable.  
> **username_0**: Thanks for mentioning the Chemex. You explain exactly why I did not include them! The flat sheet that we wrap into a cone does not need folding, indeed---there is no seam. And that's perhaps what seam folding tries to achieve: A homogeneous surface inside the filter, which is natural with the Chemex filter you mention.  

---

## 3 answers

### Answer by username_0 on 2015-02-10. Score: 4 | Accepted answer

Here is what I found:

* Trying to tear out a proper filter is difficult. Filters do resist to boiling-water temperature.
* Trying to tear out a proper filter *along the seam* is quite easy.

So, by folding the filter on the seam, it seems we kind of hide the seam from direct contact with hot water. The seam glue is *not* weak these days, but this way there is no risk of tearing (e.g. if there is a defect in the seam), and the surface area inside the filter is also more uniform---the filter stands well in place.

There is a seam in the first place, because it is easy to manufacture fold-able filters this way (I am looking for a citation here).

> **Comments:**
> **username_0**: Well, I answer my question in the end. I select this as the answer, after trying to understand *why* we end up folding filters.  

---

### Answer by username_3 on 2015-02-12. Score: 9

I did a little bit of research at the site of inventor of the coffee filter. It's Melitta from Germany. In the [german FAQ](http://www.melitta.de/de/FAQ-229.html) I found the following:

> **Warum falte ich Filterpapier vor dem Einlegen um?**
>
> Damit die Kaffeezubereitung optimal funktioniert, muss das
> Filterpapier genau in die Form des Filters gebracht werden. Dies
> geschieht, indem Sie die beiden geprägten Ränder umfalten. Das
> Filterpapier schmiegt sich dadurch an den Rand des Filters an und
> sitzt tief im Filtereinsatz. Durch diese gute Passform kann sich das
> Filterpapier während des Brühvorgangs nicht einklappen

In English:

> **Why I fold the coffee filter?**
>
> In order for the coffee preparation to work optimally, the filter paper must be brought exactly into the shape of the filter. This is done by folding over the two embossed edges. This causes the filter paper to nestle against the edge of the filter and sit deep in the filter insert. This good fit prevents the filter paper from folding in during the brewing process

Additional fact: The coffee filter was not invented by Melitta the company, but by [Melitta Bentz](https://en.wikipedia.org/wiki/Melitta_Bentz).

---

Note: The translation might have some mistakes as my English is really not the best. Please consider improving it through (suggested) edits.

> **Comments:**
> **username_0**: Thank you for your answer. I really would like the selected response to tell *why* folding matters. For this reason I choose another one as the answer, and surprisingly, mine...  

---

### Answer by username_4 on 2017-02-01. Score: 1

Good Morning coffee drinkers !

I am now getting on for 70 years old and I remember when my mother in Norfolk UK bought her first ground coffee filter machine. She used "Melitta" filters and told me to always fold the two seams. I have never forgotten this advice and along with a lot of knowledge passed on over the years I continue to do this. I settled in France around 30 years ago and have never noticed any one folding the edges over here - even my french wife has never accepted that it is necessary. However, she has, from time to time had the filter collapse when she has been responsible for preparing the coffee.....

SO - the reasons for doing this are to me, at any rate fairly clear and I agree with the reasoning of both the Melitta company & username_0.


---

