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Consistency Part 2

Exploring channeling during brewing with the Breville Oracle Touch machine.


In part 2 of my Oracle Touch Consistency exploration, I am going to use the original double basket that came with the machine, and the Breville naked portafilter that I purchased recently from Breville for about $80. We’ll use the naked portafilter to see if we can notice any channeling, or any other brewing concerns, which could point back to the grinder or tamping consistency.


For brewing, I am using a medium roast. I am going for a dose of 20g and a yield of 40g in about 27s to 30s. I am going to brew five shots and we will see what we get.


The first shot was not able to develop a nice uniform flow. It looks like two channels developed, probably because the grind size was not adequate. The yield for that shot was only 34g, instead of 40g, so channels developing to push through the puck makes sense.


For the second shot I adjusted the grind size coarser by one step, and this one was a beauty. The flow was great, and the yield was right at 40g in 28s.


The third shot was fine. It started off a little hesitant but it quickly settled and finished nicely.


The fourth shot had the huge squirt, but came out fine otherwise.


The fifth shot was a beauty from start to finish.


So, in all, without counting the first shot since the grind size was too fine, only one shot showed any signs of concerns, and it was a single spray.


Channels, squirts, and sprays usually stem from:

- Uneven grinding

- Uneven distribution - Uneven tamping - Insufficient tamping pressure

- Dose is too high or too low

- Grind size is too fine or too coarse

That covers just about everything that could go wrong with a shot, but I think that makes this short demonstration even more impressive. For the most part, the automatic grinding and tamping has mitigated most of these issues, and based on the fact that we had just one spray, I assess that this is a sign of overall good grinder consistency, and consistent distribution and tamping performance. My general experience since getting the naked portafilter, confirms this demonstration in that channels are few and far between if you are grinding at the right grind size.


So, going back to the Consistency Part 1 video, I am thinking more and more that the inconsistencies that I do encounter from time to time really come down to a dosing issue.


My overall impression about the naked portafilter: I love it! I use it every day, unless I need to make two cappuccinos at a time. It’s right for me, but it’s probably not right for everybody. Here is a quick list of pros and cons if you are considering the naked portafilter:


Pros of naked portafilter

- What I love most: It gives me much more clearance to fit cups under the portafiler

- Provides useful indications about the flow of your brewing

- It is much easier to clean

- It highlights the beauty of the espresso


Cons of naked portafilter

- It can be messy when you have a bad shot

- It’s a little pricey for a completely optional accessories


For part 3 of the consistency series, I will test brewing temperature using the scace thermofilter, a digital thermometer, and a laptop to log the data. If that is a topic that sounds interesting to you, please subscribe so that you get an alert when I post this and other new videos.



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