<h2>Tawny Foam: Taste Impact</h2>
<p>If you press all the water through the AeroPress then keep pressing, you'll press air through the grinds (making a hissing sound), and then compress the grinds and squeeze a tiny bit more water through. --&gt; The effect is to push more tawny foam through to the mug.</p>
<p>Whether that's tasty depends. Here's how to tune it:</p>
<ol>
<li>Press the water through, then stop pressing at the hiss.</li>
<li>Brace the AeroPress flange on the edge of a sink and press the plunger all the way to the end.</li>
<li>Taste the tawny foam that came through the AeroPress cap.
<ul>
<li>If the foam is sour, then grind your coffee beans finer next time and repeat this experiment.</li>
<li>If the foam is bitter, then grind your coffee beans courser next time and repeat this experiment. (Personally I find that slightly bitter coffee tastes much better than slightly sour coffee.)</li>
<li>If the foam is both sour and bitter, then grind your beans more evenly. (Maybe get a better burr grinder.)</li>
<li>If you like the foam's taste and texture, then press it into the mug in the future, otherwise press it into the sink.</li>
</ul>
</li>
</ol>
<p>The test results could vary with the coffee beans and temperature: I find AeroPress's cold brew recipe makes tastier foam.</p>
<h2>Foam and Filter: Health Impact</h2>
<p>I assume you're using a paper filter. <a href="https://aeropress.com/pages/faq" rel="nofollow noreferrer">The AeroPress FAQ</a> says metal filters pass more oils through to the mug, and <a href="https://web.archive.org/web/20170512205820/http://aerobie.com/aeropress/faqs/" rel="nofollow noreferrer">2017 editions explained</a> that paper filters remove LDL-cholesterol-raising molecules:</p>
<blockquote>
<p>Cafestol and kahweol are diterpene molecules found in coffee. They are
powerful agents that cause our bodies to increase the low density
lipoproteins (LDL or “bad” cholesterol) in our blood. Cafestol and
kahweol are removed from coffee by paper filters. <strong>Any coffee maker
using a paper filter (such as the AeroPress coffee maker) removes
virtually all of the cafestol and kahweol from the brew.</strong> We had this
verified by an independent test lab for AeroPress brewed coffee. [Bold added.]</p>
</blockquote>
<p>Also see MedicalNewsToday, <a href="https://www.medicalnewstoday.com/articles/coffee-and-cholesterol" rel="nofollow noreferrer">Can coffee raise cholesterol?</a>, or Harvard Health Publishing, <a href="https://www.health.harvard.edu/staying-healthy/whats-the-healthiest-way-to-brew-coffee#:%7E:text=unfiltered%20coffee%20contains%20diterpenes%2C%20compounds%20that%20can%20raise%20cholesterol%2C%20and%20researchers%20say%20a%20cup%20of%20unfiltered%20coffee%20contains%2030%20times%20more%20diterpenes%20than%20a%20cup%20of%20filtered%20coffee" rel="nofollow noreferrer">What’s the healthiest way to brew coffee?</a>.</p>
<p>Better detail in PubMed, <a href="https://pubmed.ncbi.nlm.nih.gov/28873752/#:%7E:text=the%20results%20showed%20that%20of%20the%20initial%20cafestol%20concentration%20present%20in%20the%20roasted%20coffee%2C%20the%20paper%20filter%20retained%2012.41%25%2C%20the%20spent%20coffee%2087.45%25%20and%20the%20brew%200.15%25." rel="nofollow noreferrer">Is cafestol retained on the paper filter in the preparation of filter coffee?</a> The paper filter holds back some of the diterpenes and holds back fine grinds and oils containing more of the diterpenes:</p>
<blockquote>
<p>The results showed that of the initial cafestol concentration present in the roasted coffee, the paper filter retained 12.41%, the spent coffee 87.45% and the brew 0.15%.</p>
</blockquote>
<p>The filtering matters with your daily brew. Here's an article where Dr. Peter Attia explains the <a href="https://peterattiamd.com/cumulative-effects-of-ldl-c-reduction-in-mitigating-cardiovascular-risk/" rel="nofollow noreferrer">Cumulative effects of LDL-C reduction in mitigating cardiovascular risk</a>.</p>
<p><strong>Q.</strong> Does anyone know if pressing the AeroPress plunger to the point of compressing the spent coffee grinds pushes more diterpenes through?</p>
<h2>Side Point: Bypass Brewing</h2>
<p>I find that bypass brewing makes significantly tastier coffee. Specifically, put 1/4 of the water through the AeroPress, then add the other 3/4 of the water directly to the mug.</p>
<p>(The AeroPress company's brewing instructions used to recommend this technique. Is it more complicated than most people want to do?)</p>
<h2>Moka Pots</h2>
<p>According to <a href="https://en.wikipedia.org/wiki/Moka_pot#Brewing" rel="nofollow noreferrer">Wikipedia</a>, the final gurgling stage is due to mixing steam into the upstreaming water, &quot;which leads to rapid overextraction and introduction of undesirable flavors.&quot; This is a different effect.</p>

CC BY-SA 4.0
2024-10-14T14:25:45.023Z
Foam and Filter: Health Impact - thanks for the links, it was an interesting read.
Jim
CC BY-SA 4.0
2024-09-17T05:52:02.363Z
2024-09-17T05:52:02.363Z
Jerry101
<p>When using an Aeropress, what's the effect of pushing the plunger to squeeze the grounds fully or not? Is it likely to make a better cup of coffee if not compressing the grounds, or always a matter of taste?</p>
<p>I'm not a coffee expert, but have noted that when using a moka pot, stopping the brew before the final gurgling stage makes a better tasting cup of coffee for me, so wondering if the same applies with Aeropress - will it be a less bitter cup of coffee if I don't push the plunger all the way to squeeze the grounds?</p>

<brewing-process><aeropress>
Aeropress - whether to push plunger to compress grounds or not?
mozboz
# Aeropress - whether to push plunger to compress grounds or not?

(Asked by: username_0 on 2024-09-06)

When using an Aeropress, what's the effect of pushing the plunger to squeeze the grounds fully or not? Is it likely to make a better cup of coffee if not compressing the grounds, or always a matter of taste?

I'm not a coffee expert, but have noted that when using a moka pot, stopping the brew before the final gurgling stage makes a better tasting cup of coffee for me, so wondering if the same applies with Aeropress - will it be a less bitter cup of coffee if I don't push the plunger all the way to squeeze the grounds?

**Tags:** brewing-process, aeropress


---

## 1 answers

### Answer by username_1 on 2024-09-17. Score: 2

## Tawny Foam: Taste Impact

If you press all the water through the AeroPress then keep pressing, you'll press air through the grinds (making a hissing sound), and then compress the grinds and squeeze a tiny bit more water through. --> The effect is to push more tawny foam through to the mug.

Whether that's tasty depends. Here's how to tune it:

1. Press the water through, then stop pressing at the hiss.
2. Brace the AeroPress flange on the edge of a sink and press the plunger all the way to the end.
3. Taste the tawny foam that came through the AeroPress cap.
   * If the foam is sour, then grind your coffee beans finer next time and repeat this experiment.
   * If the foam is bitter, then grind your coffee beans courser next time and repeat this experiment. (Personally I find that slightly bitter coffee tastes much better than slightly sour coffee.)
   * If the foam is both sour and bitter, then grind your beans more evenly. (Maybe get a better burr grinder.)
   * If you like the foam's taste and texture, then press it into the mug in the future, otherwise press it into the sink.

The test results could vary with the coffee beans and temperature: I find AeroPress's cold brew recipe makes tastier foam.

## Foam and Filter: Health Impact

I assume you're using a paper filter. [The AeroPress FAQ](https://aeropress.com/pages/faq) says metal filters pass more oils through to the mug, and [2017 editions explained](https://web.archive.org/web/20170512205820/http://aerobie.com/aeropress/faqs/) that paper filters remove LDL-cholesterol-raising molecules:

> Cafestol and kahweol are diterpene molecules found in coffee. They are
> powerful agents that cause our bodies to increase the low density
> lipoproteins (LDL or “bad” cholesterol) in our blood. Cafestol and
> kahweol are removed from coffee by paper filters. **Any coffee maker
> using a paper filter (such as the AeroPress coffee maker) removes
> virtually all of the cafestol and kahweol from the brew.** We had this
> verified by an independent test lab for AeroPress brewed coffee. [Bold added.]

Also see MedicalNewsToday, [Can coffee raise cholesterol?](https://www.medicalnewstoday.com/articles/coffee-and-cholesterol), or Harvard Health Publishing, [What’s the healthiest way to brew coffee?](https://www.health.harvard.edu/staying-healthy/whats-the-healthiest-way-to-brew-coffee#:%7E:text=unfiltered%20coffee%20contains%20diterpenes%2C%20compounds%20that%20can%20raise%20cholesterol%2C%20and%20researchers%20say%20a%20cup%20of%20unfiltered%20coffee%20contains%2030%20times%20more%20diterpenes%20than%20a%20cup%20of%20filtered%20coffee).

Better detail in PubMed, [Is cafestol retained on the paper filter in the preparation of filter coffee?](https://pubmed.ncbi.nlm.nih.gov/28873752/#:%7E:text=the%20results%20showed%20that%20of%20the%20initial%20cafestol%20concentration%20present%20in%20the%20roasted%20coffee%2C%20the%20paper%20filter%20retained%2012.41%25%2C%20the%20spent%20coffee%2087.45%25%20and%20the%20brew%200.15%25.) The paper filter holds back some of the diterpenes and holds back fine grinds and oils containing more of the diterpenes:

> The results showed that of the initial cafestol concentration present in the roasted coffee, the paper filter retained 12.41%, the spent coffee 87.45% and the brew 0.15%.

The filtering matters with your daily brew. Here's an article where Dr. Peter Attia explains the [Cumulative effects of LDL-C reduction in mitigating cardiovascular risk](https://peterattiamd.com/cumulative-effects-of-ldl-c-reduction-in-mitigating-cardiovascular-risk/).

**Q.** Does anyone know if pressing the AeroPress plunger to the point of compressing the spent coffee grinds pushes more diterpenes through?

## Side Point: Bypass Brewing

I find that bypass brewing makes significantly tastier coffee. Specifically, put 1/4 of the water through the AeroPress, then add the other 3/4 of the water directly to the mug.

(The AeroPress company's brewing instructions used to recommend this technique. Is it more complicated than most people want to do?)

## Moka Pots

According to [Wikipedia](https://en.wikipedia.org/wiki/Moka_pot#Brewing), the final gurgling stage is due to mixing steam into the upstreaming water, "which leads to rapid overextraction and introduction of undesirable flavors." This is a different effect.

> **Comments:**
> **username_2**: Foam and Filter: Health Impact - thanks for the links, it was an interesting read.  

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