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  • #16
    Re: Rossa rules!!

    Originally posted by 51606E6D6E010 link=1326844778/14#14 date=1327051287
    Maybe the inventor of the Rossa would be best to comment on this point.
    Thanks Paolo, more than happy to comment.

    Before I answer the query, Id first like to clear up a few points.

    After not being able to buy a decent portable machine (what I consider decent; individual differences are evident), I decided to make my own. The first thing I considered in relation to the design was what exactly does it take to make perfect espresso. I initially had no intention to sell the device, so I didnt care about cost. All I cared about was designing a device that made as close to perfect espresso as possible, with the least amount of moving parts, and would not break. After starring at a blank AutoCad screen for a while, I figured out that all I needed to do was design a device that pushed pressurised hot water through the coffee. Pretty simple, and that is exactly what every espresso machine is designed to do. Its just that some do it better than others. I designed the Rossa to fulfill the fundamental requirements necessary to make perfect espresso, but simplifying the design called for total manual control.

    What this means is that the Rossa is designed to do everything the same as what any good espresso machine is designed to do, but as opposed to pressing a button, you need to do it manually, which is why it is quite significantly cheaper than any machine capable of producing comparable results.

    The same rules apply equally to grind size, dosage, exaction volume, pressure, temperature, and any other variable that matters. In fact you should be able to produce almost identical results to any machine by replicating its profile. Small variations will exist due to differences in how the water contacts the puck and pump vibration frequency, but most people wouldnt notice any difference if the profile is replicated correctly.

    So, for better or worse, the Rossas greatest feature is also its biggest weakness: manual control. It must be treated like the precision device that it is, and it is important to follow the instructions exactly until you become proficient in its operation. Those who make the effort will be rewarded with unbelievable coffee.

    Originally posted by 6072626E67676464726F6E6372010 link=1326844778/13#13 date=1327045995
    Just wondering will it be easy to operate for petite female?
    I trained the Merlo girls in Brisbane and Gold Coast to use the Rossa, and all obtained good extraction. Petite girls can certainly use it well, but the standard device needs to be bedded in sufficiently and prepared correctly, and the support stand should be used. I prepared the Rossa for the girls, so maybe its not a true indicator. Nonetheless, I offer an extra long handle as an accessory for the standard device, and when combined with the support stand, almost any able bodied person should be able to use it well.

    For anyone wondering, the standard model was designed to produce what I consider the optimum pressure without needing to use a gauge. In my opinion, over-pressurisation kills the shot. The short handle makes it difficult to over-pressurise, yet relatively easy to produce the correct pressure; assuming that it is used correctly. The thread pitch produces about the correct flow rate with the natural speed that most people seem to turn the crank arm.

    The Rossa HC is easy to use as it also has the long handle. It also has a coarser thread. This provides more control for profiling, but it can be difficult to determine pressure without the gauge fitted. Once you dial in the grind and the profile for a particular coffee, it is quite easy to replicate the profile without the gauge. The HC should be easy enough for most girls to use, but the standard Rossa with long handle provides the most leverage.

    I have considered dropping the standard model and replacing it with the long handle design, but the standard design has some desirable attributes. Firstly, the shorter arm makes it more compact for travel. Secondly, during my initial experimentation with pressure profiling, I occasionally got muddled and lost my feel. Focusing too much on the gauge. Even though the shots looked visually good, they didnt taste so well. I found myself reverting back to the standard Rossa without gauge to regain my feel. This reaffirmed the merits of the standard design, but I want everyone to understand that variations are available to ensure that everyone who buys the device will be able to learn to use it well.

    I hope the above answers some questions and clears up a few misconceptions. I look forward to the day when we can discuss the pointy end of espresso evolution: pressure profiling. Come on guys, catch up! Sometimes I feel like Robinson Crusoe 

    Originally posted by 70414F4C4F200 link=1326844778/8#8 date=1327016106
    I havent been able to get as much crema with the Rossa as I do (every time) with the Cremina, so I am still working on that.
    One last thing, Im curious about the lack of crema. If possible, please send me a graphical representation of your profile. Regardless of the coffee I use (all fresh roasted), crema fills the whole shot and then separates to about half and half, then slowly settles to about a third of the shot. If the graph is not possible, let me know what you change to improve results.

    Comment


    • #17
      Re: Rossa rules!!

      If possible, please send me a graphical representation of your profile.

      Thanks, Ross.
      Here are some representations of the pressure profiling of 2 shots that I made this afternoon.

      Kindly excuse dodgy quality of the picture.
      N.B. Neither shot using PNG Kimel 10 days post roasting resulted in the quality and amount of crema that my other machines deliver with the same beans....yet the taste in both was bold and satisfying...just missing mouthfeel.

      Also worth noting is that using similar pressure profiling on other beans eg. Yirgacheffe the crema is great.

      To explain...The first graph shows pre-infusion at 2 bar pressure  from 9 seconds to 20 seconds (horizontal line) before building up pressure to 6 bar at 27 seconds. The 6 bar was maintained till the 42 second when the shot was called finished and the cup underneath was moved.

      Comment


      • #18
        Re: Rossa rules!!

        Originally posted by 1F2E2023204F0 link=1326844778/16#16 date=1327295890
        Thanks, Ross.
        Here are some representations of the pressure profiling of 2 shots that I made this afternoon.
        Nice graphs. My initial thoughts was that the 2 bar preinfusion is too high. I have found that too high a pressure floods the puck too much. My theory is to apply just enough pressure to gently push the water into the puck without too much disturbance or harshness. Too much preinfusion overly wets the puck, which makes it difficult to obtain maximum extraction pressure. It is generally necessary to user a finer grind, but that can lead to some nasty tastes coming through. I generally preinfuse on about 0.5 bar of just above, but Im starting to move away from a pause and favouring a slower and smoother buildup. I still preinfuse for about the same time, but just do it without pausing. Well thats been the theory for the last few weeks anyway!

        Before I sat down to reply to this, I thought Id better replicate your profile. I took it to 2 bar, paused, and was then surprised that the pressure came up quite easily. So that blew away the too much preinfusion hypothesis! I used some Peru, and the shot was all crema for a while before it settled. Was very nice, so intend to play with that profile some more. That doesnt help your issue though.

        If you get good extraction on your other machine, but cant get the same through the Rossa, I suggest to replicate the other machines profile. All things equal, the shots should look very similar.

        If you are getting good extraction from one coffee, but not from another, it would suggest that the coffee is a bit temperamental with regards to extraction profile.

        If you have already replicated the profile without success, and assuming the extraction temperature is the same, the only other variable I can think of is how steady the device is operated. Too many stop starts, pauses or rough operation can influence the shot. When chasing perfection, it is important to keep the flow before and during extraction as smooth as possible so pressure changes are as seamless as possible. An accurate graph would look similar to the profile of a wave on a calm day before it breaks, as opposed to the same wave on a windy day. That said, this much attention is really only needed if youre trying to reach perfection and extract the most subtle flavours. Bad shots generally still look good.

        If replicating the profile doesnt work, skip the preinfusion completely, and take it to 8 or 9 bar. Assuming this gets a better looking shot, work back to find the best balance between pressure and preinfusion.

        Thats enough to play with for now. Let me know how you go.

        Comment


        • #19
          Re: Rossa rules!!

          I just solved a problem I have been having with one of my Rossas, which is the puck falling out when inverted to screw onto the body.
          It wasnt happening all the time, but often enough to be very annoying, especially as I am on limited beans, being on board my ship shuffling backwards and forwards from Australia to Japan, and the only thing to do was to make another shot, wasting a shots worth of beans.

          An immediate clue that the shot isnt going to work correctly, is what comes out the spout after the Rossa is inverted after screwing on the PF, if a small amount of clear water comes out, all is well with the shot, if it is weak coffee coloured, the puck has fallen out, an the shot will be rubbish.

          The reason for the post, it to disseminate the cause, and the fix.

          The cause proved to be poor leveling before tamping.

          The fix, is to deliberately bias the tamp to the outside, by actually making a slight depression in the centre of the pre-tamp puck, so it clings to the side of the PF basket harder.

          I am using Oomph Romeo beans, ground to two clicks off closed in a Kyocera hand grinder.

          I will have to resort to Jamaica Blue whole beans at the the end of this, the second of 3, trips, as 2 kilos of beans only go so far, and I know the problem is worse with older beans, like "no clue when they were roasted" Jamaica Blue beans.

          Hope this helps others, as I still love my Rossa, thanks Ross.

          Comment


          • #20
            Re: Rossa rules!!

            Originally posted by 4E616B7622486E6B686A7B0F0 link=1326844778/18#18 date=1332479067
            I just solved a problem I have been having with one of my Rossas, which is the puck falling out when inverted to screw onto the body.
            It wasnt happening all the time, but often enough to be very annoying, especially as I am on limited beans, being on board my ship shuffling backwards and forwards from Australia to Japan, and the only thing to do was to make another shot, wasting a shots worth of beans.
            Thanks for the feedback Andy.

            It is very important to tamp the puck correctly, otherwise it could dislodge as you note. Its not necessary to apply undue force, but sufficient force is required. I push down and rotate the tamper back and forth several times to "polish" the puck, for want of a better term. I also turn the filter head around a few times and repeat the tamping polishing action taking note to ensure the puck is level. This process only takes a few seconds, and it seems to compact the puck very well so that it grips the basket and stays secure. The more I think about it, insufficient tamping is probably the likely cause of the crema differences noted above.

            I encourage anyone who is having trouble learning to master the Rossa to contact me for assistance. It is a remarkable device, and its profiling capabilities push beyond the limits of conventional espresso understanding. Ive also been experimenting with a declining temperature profile, and results are promising. I take pride in the understanding that what I do over my humble kitchen sink is at the pointy end of coffee extraction development. However, all is lost if others are unable to push these same limits. Do not accept "great", aim for perfection.

            P.S. More Pressure Profiling Adapters will soon be available. They will include details of my pressure and temperature profiling experimentation so that, hopefully, others can build upon.

            Comment


            • #21
              Re: Rossa rules!!

              My tamping is a little different (I have never had a puck coming adrift). The plastic tamper is undersized, so I run it around the rim of the backet on a slight angle so the edge is lower than the centre; then I use pressure on the centre of the basket to tamp; then clean up around the edges; then polish gently. Note I am using a Rosco grinder that leaves a consistent, fairly firm puck anyway.

              I will eventually get a metal tamper exactly sized to the basket, which will avoid all the mucking about - I guess I just baulk at the cost of such as item. Perhaps I can convince my B-i-Law to turn one for me in stainless steel on his lathe - handle and all!

              I am not complaining about the coffee quality - I now consistently get 30ml of crema infused coffee. I am using fresh roasted Beanbay beans, if that makes a difference.

              Cheers
              Peter

              Comment


              • #22
                Re: Rossa rules!!

                Hi,
                I gotta say these Rossa hav got my creative juices flowing. I saw a set at Merlo recently and before I know it Ive spent way too many hours readn this forum. Missus reckons Im playn up. Lol. Anyway just gotta save up th pennies...
                Cant wait...
                Thanks to those takin th time to share their stories...
                Much appreciated
                Andrew

                Comment


                • #23
                  Re: Rossa rules!!

                  Originally posted by 5E5357405758455754594053360 link=1326844778/20#20 date=1333168828
                  The plastic tamper is undersized,
                  Hi Peter,

                  A few people have commented about the tamper size. I actually like it with a bit of clearance, which is why I made it that way. However, if a tighter fit is preferred by more people, I will change it. The tamper is a machined item, so dimension accuracy is not an issue. Its made from a hard plastic and smaller in length than standard to make it light weight and more portable. I might even look at adding a standard type metal or brass tamper as an accessory if there is any interest.

                  Ross

                  Comment


                  • #24
                    Re: Rossa rules!!

                    Ross,
                    I much prefer the full-sized metal tamper I have for the La Pavoni - which only gets used for visitors now a days; the stubby tamper design I think is good. Having said that, for travel, plastic is probably the way to go. The biggest problem for full sized I guess is the variation in basket size.

                    Cheers
                    Peter

                    Comment


                    • #25
                      Re: Rossa rules!!

                      I am saving up for this as we speak!

                      high-end with low tech

                      right up my ally. I am really impressed!

                      Ross is leading the way to understanding true coffee profiling.

                      Comment


                      • #26
                        Re: Rossa rules!!

                        Originally posted by 744B5650455754564157574B240 link=1326844778/19#19 date=1332731234
                        P.S. More Pressure Profiling Adapters will soon be available. They will include details of my pressure and temperature profiling experimentation so that, hopefully, others can build upon.

                        I am very interested

                        keep us posted Ross

                        Comment


                        • #27
                          Re: Rossa rules!!

                          Originally posted by 1D73333F305E0 link=1326844778/24#24 date=1340789029
                          Ross is leading the way to understanding true coffee profiling
                          Hi C-man,

                          Thanks for your confidence in what Im doing! The info Ive made public so far is available at http://www.portaspresso.com/page0051.html

                          Ive since tested quite a number of profiling variations and I still feel that staying below 6 bar with the correct preinfusion and ramp-up profile is the way to go. In particular, the ramp-up profile (pressure over time) appears to be a very significant variable. I will post more on this at a later date.

                          While Im here, I would like to retract something I wrote previously on this site, which is the possible effects of vibration pumps on espresso quality. Ive since been able to reproduce the adverse visual and taste characteristics I previously attributed to the vibration pump without a conventional pump. Vibration and frequency was zero, but the shot was the same. Altering the ramp-up profile alone completely changed the shot from one of bubbly crema and harsh taste to one of smooth rich crema and matching smooth rich taste. The same effect applied regardless of extraction pressure, but my personal preference is for the lower pressures.

                          Anyway, Ill leave it there for the moment. As always, thanks everyone for your feedback both private and public. I appreciate it and I use it to drive product improvement and development of new ideas.

                          Stay tuned!

                          Ross

                          Comment


                          • #28
                            Re: Rossa rules!!

                            This is what fascinates me,

                            having manual control of everything allows you to break all the rules and experiment.

                            Comment


                            • #29
                              Just spent 6 weeks on the road using a Rossa daily to make my two AM long blacks, ,my personal observations are as follows.

                              I used beans roasted immediately prior to leaving home, the flavor and overall result in the cup was superior to any plunger type coffee maker I have ever used (closest thing to espresso yet) however never once did I manage to pull/express a shot with the slightest hint of crema.

                              The device is very nicely made and is nice to look at and hold, sadly I found it far from user friendly, heating it up was no problem, after screwing the filter holder in, lubricating the screw with water and inverting the device and locating it in its tripod the winding begins, we are told the first few uses the screw will be quite stiff, this is an understatement, I found it to take about 20 uses to loosen up, even then it takes more than just a little strength and coordination to carry the operation out, it tends to rock around on the tripod and requires quite a bit of effort and concentration to hold steady, clean up for a second shot is slow and messy, dismiss any thought of making morning coffee for half a dozen friends, its a slow laborious process, and the operation would take up a good slice of your AM.

                              Take care when setting the device up, if you lay it down on a flat bench that is not level the thing will begin to roll quite quickly, I saved it from hitting the deck a couple of times before I learned to position it so it would not take off on its own.

                              Lubricating the screw with water is messy and not very effective, as the device has been preheated the water on the screw has mostly evaporated before you start the winding process, even after 6 weeks of daily use its still quite stiff to wind in and the knob on the winder handle has developed a squeak that SWMBO claims sets her teeth on edge.
                              Will I continue to use it? yes (it cost me $400) until a better and more user friendly solution comes along.

                              Is it easy/simple and quick to use? far from it.

                              I will post my thoughts on the grinder elsewhere.

                              Comment


                              • #30
                                A couple of thoughts after 8 months of daily use (short blacks):

                                Originally posted by Yelta View Post
                                Just spent 6 weeks on the road using a Rossa daily to make my two AM long blacks, ,my personal observations are as follows.

                                I used beans roasted immediately prior to leaving home, the flavor and overall result in the cup was superior to any plunger type coffee maker I have ever used (closest thing to espresso yet) however never once did I manage to pull/express a shot with the slightest hint of crema.
                                Comment: I find I need to grind beans much finer than the Manual, ie around 4 large divisions on the ring - and I get good crema. I use 18-20gm of beans. I use coffeesnob roasted beans mainly, and I think quality, fresh beans essential

                                Originally posted by Yelta View Post
                                The device is very nicely made and is nice to look at and hold, sadly I found it far from user friendly, heating it up was no problem, after screwing the filter holder in, lubricating the screw with water and inverting the device and locating it in its tripod the winding begins, we are told the first few uses the screw will be quite stiff, this is an understatement, I found it to take about 20 uses to loosen up, even then it takes more than just a little strength and coordination to carry the operation out, it tends to rock around on the tripod and requires quite a bit of effort and concentration to hold steady, clean up for a second shot is slow and messy, dismiss any thought of making morning coffee for half a dozen friends, its a slow laborious process, and the operation would take up a good slice of your AM.
                                comment: I find adding dishwashing detergent to the lubricating water every few uses makes a huge difference to the stiffness of the winding.

                                Originally posted by Yelta View Post
                                Lubricating the screw with water is messy and not very effective, as the device has been preheated the water on the screw has mostly evaporated before you start the winding process, even after 6 weeks of daily use its still quite stiff to wind in and the knob on the winder handle has developed a squeak that SWMBO claims sets her teeth on edge.
                                comment: wiping the screw with a very wet cloth makes winding easier. I am thinking of using some food quality grease as an experiment

                                Originally posted by Yelta View Post
                                Is it easy/simple and quick to use? far from it.
                                comment: I agree there is a learning curve, and it is not easy to get it right. However the benefits are significant - espresso as good as anywhere, at a reasonable cost (compared to machinery), acceptable mess, minimal cleaning, no permanent bench space required, travels well (2 months is US recently + other trips), some upper body exercise. I am now comfortable with the gear, and make a cup in c. 6 mins from arrival at bench

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