Pressure profiling

[Zaneus]

you can set the ramp down to happen after a certain amount of the shot has been brewed. So he's dropping his pump pressure to (what i assume?) is 7bar after 95% of the shot has brewed. So it's only really dropping down for the last two or three seconds.

[muppet_man67]

Tried this, 7 second preinfusion and 3 second ramp up. Set the ramp down to 95%. Crema so thick it can barely escape the basket. delicious full flavoured through milk, a little acidic black. Amazing. Just amazing.

I'm not too familier with Hydra's what effect does 95% ramp down have on the pressure profile/curve?

Any theories on what it's doing to the coffee to make it taste like this?

[potentialfig]

I also have a 7 second preinfusion at 7 seconds and a ramp up to 7bar for a further 3 seconds (though i dont really believe thats necessary) then full pressure. Preinfusion helps with consistency as well but i notice a decrease in body.

Tried this, 7 second preinfusion and 3 second ramp up. Set the ramp down to 95%. Crema so thick it can barely escape the basket. delicious full flavoured through milk, a little acidic black. Amazing. Just amazing.

[TOK]

...........Results in the cup are not definitive

And totally irrelevant once the espresso base is turned into a milk drink which is what the majority of clients buy, especially in takeaway sized containers which are also a high proportion of what the clients buy.

[MrJack]

Re: Pressure profiling

Oh, of course, I forgot about the 3way valve... Might rig up a pump bypass switch for testing... Vib pumps ramp up pressure over a period of a fair few seconds though (from what I've measured on my machine), don't they? So it should be fairly gentle.

The BES820 has a 'preinfusion phase', where it cycles a few times before pausing, and then going to full flow. If you hit the brew button again, just before this phase ends, and then once again quickly, you can repeat this phase again without the machine purging. It will purge if you're too slow turning it back on. :thumbdown:

Results in the cup are not definitive

[Zaneus]

Thanks for the thoughts guys. with so many variables it seems there are infinite ways to skin this cat.
Ok, now I have a computer in front of me and not a mobile phone I can give a little more detail.

I'm running a 3x volumetric machine, would have loved a paddle, but the machine was ordered before I found this place (and yes the owner would have got a 2x volumetric, 1x paddle if I asked). I am running a relatively sweet blend from 5 senses which I am dosing at 23g for a 9bar extraction to get enough body to push nicely through milk. I have a three grinder setup for (at the moment) just one blend and decaf. Primary is an auto Robur, with a auto kony(?) as my play time grinder.

When I am experimenting I isolate one group and dial in my second grinder, its a good luxury to have because I don't have to worry about feeding the customers random stuff. I am trying to leave dose and temp constant to remove some variables. And for the sake of repeatability everything is weighed and recorded.

So far I have found that introducing a ramp down to 7 bar for the last 5-7 seconds of extraction seems to, as far as flavour is concerned balance out some of the inconsistencies that the automatic dosers on the mazzers have, giving me a broader range of extraction times that still taste awesome.

Will keep everyone posted as I keep going.

Ive had similar experiences with the end of brew ramp down stage. Also we started out with a very similar setup from five senses. Two roburs and a kony, 3 group hydra (paddle, vol, vol) and a custom houseblend. We've since started roasting our own coffee, but i still notice the same thing in regards to that ramp down. It tends to remove inconsistencies between each coffee i make and coffees other baristas make. Too long and it can start to lose a bit of intensity. If i push that ramp down to 5-7 seconds i notice a bit of unpleasant acidity starting to shine through. I'm not saying my method is correct as there are a bunch of other factors, but my sweet spot has been to ramp down after 92% of the shot is complete.

Its useful for 'saving' a shot of espresso too, if you're using a paddle. If you can see that the shot is going to blonde early for whatever reason, you can ramp the pressure down for the last 7-10 seconds and still have a drinkable shot of espresso. Its still better to just sink it and prepare another though, heh.

[potentialfig]

Thanks for the thoughts guys. with so many variables it seems there are infinite ways to skin this cat.
Ok, now I have a computer in front of me and not a mobile phone I can give a little more detail.

I'm running a 3x volumetric machine, would have loved a paddle, but the machine was ordered before I found this place (and yes the owner would have got a 2x volumetric, 1x paddle if I asked). I am running a relatively sweet blend from 5 senses which I am dosing at 23g for a 9bar extraction to get enough body to push nicely through milk. I have a three grinder setup for (at the moment) just one blend and decaf. Primary is an auto Robur, with a auto kony(?) as my play time grinder.

When I am experimenting I isolate one group and dial in my second grinder, its a good luxury to have because I don't have to worry about feeding the customers random stuff. I am trying to leave dose and temp constant to remove some variables. And for the sake of repeatability everything is weighed and recorded.

So far I have found that introducing a ramp down to 7 bar for the last 5-7 seconds of extraction seems to, as far as flavour is concerned balance out some of the inconsistencies that the automatic dosers on the mazzers have, giving me a broader range of extraction times that still taste awesome.

Will keep everyone posted as I keep going.

[Dragunov21]

Oh, of course, I forgot about the 3way valve... Might rig up a pump bypass switch for testing... Vib pumps ramp up pressure over a period of a fair few seconds though (from what I've measured on my machine), don't they? So it should be fairly gentle.

[Zaneus]

Hi potentifig,

I'm also looking into getting a Hydra 2. Was curious what pressure profiles have you experimented on and what are the results. I'm looking more into getting a good cup of coffee consistently so might opt for the volumetric one which should be more consistent if the dry grind coffee is consistent. What are your thoughts??

Volumetric machines help with consistency tremendously and can do everything the paddle version can do. The paddle really is only useful for one off pressure profiles. for instance you want to see what an extended preinfusion tastes like you can do that straight up on the paddle. for the volumetric buttons you have to program it. I'm assuming this is for a cafe setting? I find the paddle way way more useful for dialing in coffees, but use the two other volumetric groups during the day, using the paddle for single origins and the like.

The other big plus to the hydra or any other machine similar to it, is the fact that its got three pumps and three brew groups. Its comforting knowing that if something fails you can probably still make coffees all day.

@dragunov: Sort of but not really. When i had a silvia i used to do quick half second bursts on and off again for a few seconds. It helps saturate the puck slower and is technically a preinfusion, but it's not as gentle as a 3bar 'real' preinfusion.
The other downside is as soon as you deactivate the pump the solenoid valve releases and sucks out the preinfusion water. think of how backfulshing works and imagine that with coffee you're trying to brew. I can't really remember if my fake preinfusion tasted any better or worse, so you'll have to do some experimenting yourself.

[Dragunov21]

Here's a question; can you get effective preinfusion on a basic vib-pump machine by switching it on then turning it off for x seconds as soon as you start to see beading on the bottom of the basket then turning it back on?

[muppet_man67]

Something you may find interesting, potentialfig, from David Schomer's recent review of the NS Aurelia:

I guess it depends on whether you think stable pressure or stable flow are more important. We know that you can get awesome but different espresso from a Multiboiler a Lever and an E61, all have unique pressure/temperature profiles.

Multiboiler = flat pressure/flat temperature,

Lever = declining temp/pressure,

E61=flat pressure/slightly declining temperature.

All three have slightly different pre-infusions too.

"Best" flavour profile, imo is subjective and its within a subjective realm of correctly extracted espresso that pressure profiling occurs. It ought allow us to make subjective choices about what we prefer and how we want our customers to experience the coffee. For me, I'm looking for what tastes yummiest (in my mind) with lots of sweetness and body. Others might be chasing clarity of flavors and origin differentiation. Those two different approaches are both valid but will result in different tasting although objectively correct extracted espresso.

If it's about intensity than perhaps one would have a different pressure profile for when your serving with milk compared to serving straight espresso.

[Zaneus]

Re: Pressure profiling

Yes, generally around the 25s mark for a 48ml double. 93.5 degrees c, 20g dose, coffee roasted a degree before 2nd crack. Ive experimented several times now and had the same decrease in body every time. Not sure if ive tried other coffees though (probably not)

[muppet_man67]

I also have a 7 second preinfusion at 7 seconds and a ramp up to 7bar for a further 3 seconds (though i dont really believe thats necessary) then full pressure. Preinfusion helps with consistency as well but i notice a decrease in body.

Interesting that we are finding different things, just goes to show how complicated it can all get. I know I need to experiment more with pre-infusion so I can quantify better the exact effect in the cup.

Are you readjusting for the faster flow, ie grinding finer to get the same final brew weight in the same time?

[simonko]

Something you may find interesting, potentialfig, from David Schomer's recent review of the NS Aurelia:

"My interest is in the coffee but they have packed in plenty of the latest modern advances, with the notable exception of pressure profiling. Good job Simonelli, they ignore the latest gimmick in machine design because they actually know how to make this coffee. ( Stable pressure throughout the brewing cycle will give you the best flavor profile. Changing pressure during the extraction is like changing the temperature and will reduce flavor intensity…the two factors are intimately intertwined)."

[hyperwave]

Hi potentifig,

I'm also looking into getting a Hydra 2. Was curious what pressure profiles have you experimented on and what are the results. I'm looking more into getting a good cup of coffee consistently so might opt for the volumetric one which should be more consistent if the dry grind coffee is consistent. What are your thoughts??