I'll have to compare an AeroPress brew with a Robot extraction, and maybe I'll get out the brix meter to check it out. Don't know when I'll get to it. The reference point remains from years ago when Alan Adler bested by La Pavoni shot. I think the grinds were similar.

vit wrote:I didn't understand what's the problem with the gasket you have. I usually heat it up to near the opening pressure of the security valve, sometimes to that pressure, all that happened so far was that the security valve started opening ... it's not hard to estimate how high you are with the pressure from the power of the steam

If the pressure gets high enough the 4" red gasket seated underneath of the lid will be blown out of place in a rather loud and fantastic explosion of steam.

I agree it's not an issue that's difficult to avoid by any means, but unlike a larger machine, you have to keep an eye on it. Anyway, I'm not knocking the bellman. I love its simplicity and portability. I'm definitely a fan. And when used correctly the quality and texture of the milk it will make is as good as any. I was just commenting on my experience with the unit and what I believe are some misconceptions about it, the main one being that it has difficulty frothing or steaming milk. It doesn't! But at the same time I have to acknowledge that learning to get the very best results with the bellman may take a bit longer than it would on a bigger, fancier machine that benefits from significantly higher volume and pressure. But once you have it down the results are excellent.

drgary wrote:I'll have to compare an AeroPress brew with a Robot extraction, and maybe I'll get out the brix meter to check it out. Don't know when I'll get to it. The reference point remains from years ago when Alan Adler bested by La Pavoni shot. I think the grinds were similar.

That will be interesting to see. I've never attempted an Aeropress shot greater than about 4.5% strength because it seemed ludicrous to me to throw away so much in terms of solubles. And even those brews I did only for the sake of experiment. So my calculations are an extrapolation. A very reliable extrapolation, I believe, but not based on direct experience at 10% strength.

jpender wrote: That will be interesting to see. I've never attempted an Aeropress shot greater than about 4.5% strength because it seemed ludicrous to me to throw away so much in terms of solubles. And even those brews I did only for the sake of experiment. So my calculations are an extrapolation. A very reliable extrapolation, I believe, but not based on direct experience at 10% strength.

Meanwhile, for experiment, the OP can try an extraction by taste. Infuse for a few minutes, try to match strength. Again, I don't know when I can get to it.

Jakuka wrote: If the pressure gets high enough the 4" red gasket seated underneath of the lid will be blown out of place in a rather loud and fantastic explosion of steam.

Really? Never happened on mine, and as I said, a number of times I went to pressure that started opening the security valve. Most funny thing on mine is loud shaking at the beginning, due to explosive water boiling under vacuum. I posted a video about that a while ago

Any chance to post a video about your issue ?

1. Never had the gasket blow although I've heard of it happening. Sounds scary, thought it was due to user error but perhaps it could be a worn gasket? I turn off the heat when the safety valve opens - about 3 bars AFAIK, hence the powerful steam. If using the CX-25P with a gauge I guess it would be easy to stop at a determined point instead.

2. Speaking of explosions, that's what can happen to the internal components of an induction stovetop if the vessel is not absorbing enough energy (but perhaps not so likely in such a short duration).

3. About aeropresso, I needed to use exactly double the amount of grinds to achieve the same strength using the recipe described at https://www.javapresse.com/blogs/aeropr ... sso-recipe but stirring instead.

First try: same grind I use for a 20g VST basket yielded a "1:2.2 shot" at 5% strength. In hindsight I should've pressed down on a scale to be able to calculate pressure, but it was only firm so perhaps about 0.35 bar.

Second try: much finer grind, enough to choke even the Robot. The grounds seem to absorb only slightly less water than its own weight. 35.3g in, 75g brewing water yielded 40.7g out at ~9.6% strength. Due to the fine grind it was difficult to mix properly, resulting in a infusion time of almost a minute. Had to lean with most of my weight to be able to push through, operating at what feels like the upper limit of the aeropress and perhaps 1 whole bar of pressure for a total brew time of 2 minutes. The taste was a bit bitter and more similar to what I'd expect from a moka pot than an espresso machine, but not too bad. The first try was much better though. No crema with either brew but I was using a paper filter.

I think the extraction is actually high, but basically half of the shot is left behind with the grinds since they're not diluted like with espresso or drip and the brew water is so much less than a normal infusion brew.

4. I was using 202F/94C water since I thought it would extract more. In what way would 176F/80C benefit extraction, or is it just a way to limit bitterness?

5. I'd use a Bellman to make faux espresso. CX-25/CX-25P is like a Bialetti Brikka with more control and fairly decent results.. OR just buy the Cafelat Robot - in my experience it's worth it for flavour, ease of use/maintenance and long term savings.

Jonk wrote:The grounds seem to absorb only slightly less water than its own weight. 35.3g in, 75g brewing water yielded 40.7g out at ~9.6% strength.

Actually the grounds would have absorbed *more* than their original weight. Remember that while you started with 75g of water you actually got about 83g of liquid because of ~8g of dissolved solids. So there would have been about 42g of liquid coffee trapped in the grounds. I've been able to get out a little more of the trapped liquid by really pressing hard at the end and also remembering to collect the half spoonful or so that inevitably gets stuck in the Aeropress cap.

Jonk wrote:I think the extraction is actually high, but basically half of the shot is left behind with the grinds since they're not diluted like with espresso or drip and the brew water is so much less than a normal infusion brew.

The fact that you were able to get it to work with double the grounds suggests that your Aeropress extraction was a little higher. The numbers I get are 22.7% immersion extraction with your Aeropress versus 22.1% with your espresso machine.

Thanks for reporting this experiment.

Jonk wrote:I was using 202F/94C water since I thought it would extract more. In what way would 176F/80C benefit extraction, or is it just a way to limit bitterness?

Exactly. It takes too long to press so overextracted flavors are hard to avoid, except by grinding more coarsely, which reduces total extraction. By dropping the temperature you can extract pretty high without the bitterness. It depends on the coffee but with a darker roast I've gotten 25% extraction -- quite drinkable -- with my Aeropress that way.

Jonk wrote:5. I'd use a Bellman to make faux espresso. CX-25/CX-25P is like a Bialetti Brikka with more control and fairly decent results.. OR just buy the Cafelat Robot - in my experience it's worth it for flavour, ease of use/maintenance and long term savings.

I used a Brikka for years as my "espresso" substitute. I got 60ml shots in the 5-7% range. I liked the Brikka coffee a lot and found it very forgiving and easy to control. When I got a Robot I intended to do a side by side comparison of the shots. But the Robot shot quality was such an obvious, in your face improvement that I still haven't done this comparison. It's been over ten months since I got my Robot and last touched my Brikka. I really should get it out and do the side by side test... but not today. Nope.

vit wrote:Really? Never happened on mine, and as I said, a number of times I went to pressure that started opening the security valve...

UPDATE:

After hearing about others having the same 'explosive' experiences that I did I had always assumed it was the nature of the machine. However, reading your comments really had curious as to whether something else going on. You've indicated twice now that the security valve is a reliable indicator for you as to when the steamer is ready. This wasn't the case for me. I was getting very trace amounts steam coming out from the valve--- an amount that would easily go unnoticed. So...I tried propping the steamer up in the corner, on its side, with the handle pointing down. Then I placed a few drops of white vinegar inside of the valve and let it set for a few hours. Afterwards I gave it a quick rinse and filled it up to give it a little test. Bingo...that seemed to do the trick. I'm now getting a significant amount of steam coming from the valve once the unit is ready.

Not really sure how the valve would have gotten stuck to begin with. Aesthetically speaking the unit still in like new condition, inside and out, as I only use it for guests. Although, maybe it's possible that going several weeks between uses may have contributed to mineral deposits or the valve mechanism freezing up....I don't really know. Visually, it looked clean. But anyway, this definitely kicks the Bellman up a notch for me in terms of user friendliness. Before I found myself wishing it had a pressure gauge to make it easier to monitor with having to man the stove. I was ready to consider modding the steamer to add a gauge. But with the valve working properly I don't think it's needed. Thanks for chiming in about that....otherwise I may not have considered investigating further.

So it was actually stuck security valve? Nice that you fixed it. I did measure the temperature of opening of the valve and it was quite precise, between 152 and 154°C measured by the probe put near the security valve, which is about 5 bar (it's very unlikely that the probe measured higher temperature than inside the steamer). I don't like the idea of having a vessel with 5bar near my head, but it happened a number of times that it reached opening pressure just in the middle of the pull with Flair, as my induction stove heats it very fast. Usually I start steaming before the valve starts opening, as there is more than enough pressure

However, I have a new version of the tip with 2 holes, which I drilled from original diameter (around 0.8mm) to about 1.2mm, as it looked too small for me (didn't even try steaming before that), so steam is surely stronger at the same pressure. At work, I was used to steam the milk on the office superauto that has 2l boiler and 3 x 1.5mm hole tip ...