CoffeeBar wrote:No, I found these reviews are very useful for me. The only downside was like what you said here, the shipping time need to wait until February and I want the machine before Chinese New Year

and thank you Tom for this details review here

"Worse" as in making me to want to buy it *more*.

cpreston wrote:The main point of its technology is that is doesn't need a boiler or a pstat. It uses computer controlled thermoblocks.

After a week on tour, enough engineering/coffee nerds have talked to me about our water heating approach, that I think I prefer to describe it as a "hybrid" approach, not entirely like a boiler, but not completely other either.

The reason for this change of terminology is that we "sort of" do have a boiler, it's just that it heats the 2 liter water container (which is ceramic) to 50°C, not boiling, and it does so with a circulator, like some sous vide machines do. It doesn't boil the water, though, so it's not really a boiler.

We do not heat room temperature water up to brewing temperature with a thermoblock. We tried that, and as long as Ray (my internals engineer) was in the room, it worked great. Otherwise, it did not, and it made bad coffee. Thermoblocks are not good at handling the variable flow rates that espresso produce, and tend to overheat the water when the flow slows down a lot.

So, we developed a hybrid approach that combines ideas from boilers, on-demand, water mixing, and saturated groups (phew, that's a mouthful).

Our water heating approach has four components:
- we preheat the water tank water to 50°C. That allows us to have a smaller jump to ~92° for brewing, and also allows us to have instant and long lasting steam.
- to make espresso, we use a thermocoil to heat the water about 5°C hotter than the set point. I say "about" because the thermocoil is not a very accurate technology, and is off by a few degrees. A PID controls the on demand heating.
- we then introduce, in a water mixing chamber, a slow stream of 50°C water to bring the slightly-too-hot water down to the desired temperature. We have two separate pumps: hot and hold. Another PID controls the mixing ratios.
- one last wrinkle is that our group head has a PID controlled electric heater in it, so that the group head does not destabilize the water mix (ie, cooling the water, as many group heads do).

Preheating 2 liters of water to 50C will take how long from cold start? Will preheating be ongoing for as long as the unit is plugged to an AC socket?

It takes about 4 minutes with cool tap water to heat 2 liters to 50°C. The preheating is ongoing, and as we have spare electricity (ie not making shots) we will raise the water to (a) sterilize it and (b) if you buy the pro version with the plumbing option, the water tank is kept topped up. And, since the water was above 50°C and only a little bit of cool water is added at a time, there's no need for the machine to pause between shots. If you don't have the plumbing kit and the tank goes to empty, there's a 4 minute wait time for the tank to get heated back to 50°C again. However, 2L is a LOT of shots, about 10 to 20, in my experience, depending on whether you're making Americanos or not.

If you tap the "power off" icon on the tablet, the preheating of the tank stops -- all heating stops, and the screen saver is displayed on the tablet. This happens automatically after (default) 30 minutes of inactivity (user configurable). Tap the screen saver and the machine comes back to temperature, within 4 minutes.

JojoS wrote:Preheating 2 liters of water to 50C will take how long from cold start? Will preheating be ongoing for as long as the unit is plugged to an AC socket?

decent_espresso wrote:It takes about 4 minutes with cool tap water to heat 2 liters to 50°C....

If folks have questions for the vendor, please post in the Marketplace thread where they're free to engage with them as much as they want. Remember, the general discussion forums don't allow for back and forth replies from vendors. I started this thread to share my interest and thoughts in the Decent Espresso machine and folks are free to comment about their thoughts, but it's not the place for vendors to answer questions.

Thanks.

Tom and members, I'm not sure if this has been put forth, if so, apologies. I didn't want to post this on a pre-order thread.
Would any folks here (myself included) be interested down the road in a NON STEAMING Plus model? It seems to me it would un-complicate things greatly, and those who need steam would have THEIR alternatives. I'm speaking well down the road, of course. John has his ands full as is.

TomC wrote:I was very fortunate to host both Dan (HB) and John of Decent Espresso on a trifecta of chance that had all of us here in the bay area yesterday. .... I took a few pictures and filmed a few short videos on my Instagram.

I went to the Instagram and found myself dealing with an involuntary mouth watering event. The brisket pic is killer - please start home-bbq.com

All kidding aside, thanks for doing this review. Delivery for the final version is April.

decent_espresso wrote:After a week on tour, enough engineering/coffee nerds have talked to me about our water heating approach, that I think I prefer to describe it as a "hybrid" approach, not entirely like a boiler, but not completely other either.

The reason for this change of terminology is that we "sort of" do have a boiler, it's just that it heats the 2 liter water container (which is ceramic) to 50°C, not boiling, and it does so with a circulator, like some sous vide machines do. It doesn't boil the water, though, so it's not really a boiler.

We do not heat room temperature water up to brewing temperature with a thermoblock. We tried that, and as long as Ray (my internals engineer) was in the room, it worked great. Otherwise, it did not, and it made bad coffee. Thermoblocks are not good at handling the variable flow rates that espresso produce, and tend to overheat the water when the flow slows down a lot.

So, we developed a hybrid approach that combines ideas from boilers, on-demand, water mixing, and saturated groups (phew, that's a mouthful).

Our water heating approach has four components:
- we preheat the water tank water to 50°C. That allows us to have a smaller jump to ~92° for brewing, and also allows us to have instant and long lasting steam.
- to make espresso, we use a thermocoil to heat the water about 5°C hotter than the set point. I say "about" because the thermocoil is not a very accurate technology, and is off by a few degrees. A PID controls the on demand heating.
- we then introduce, in a water mixing chamber, a slow stream of 50°C water to bring the slightly-too-hot water down to the desired temperature. We have two separate pumps: hot and hold. Another PID controls the mixing ratios.
- one last wrinkle is that our group head has a PID controlled electric heater in it, so that the group head does not destabilize the water mix (ie, cooling the water, as many group heads do).

Is there a separate element for preheating the reservoir or does it pass through the coil and back out into the tank? Forgive my math here if its totally wrong but would it be accurate to say you would need to apply 942 watts of heat for your before-mentioned 4 minutes to bring the temperature of the reservoir (2000 grams of water) from 23C (room temp) to 50C?

jwCrema wrote:I went to the Instagram and found myself dealing with an involuntary mouth watering event. The brisket pic is killer.

I just checked it out and you weren't kidding. I'm also craving a nice beer along with my red meat and espresso

IMAWriter wrote:Tom and members, I'm not sure if this has been put forth, if so, apologies. I didn't want to post this on a pre-order thread.
Would any folks here (myself included) be interested down the road in a NON STEAMING Plus model? It seems to me it would un-complicate things greatly, and those who need steam would have THEIR alternatives. I'm speaking well down the road, of course. John has his ands full as is.

I would