Given the other machine performs consistently I'd be interested if the machine delivers the same amount of water per unit time if it does, then maybe puck preparation might be inconsistent? You're using the same grinder on the Express?
The basket size differences might be sensitive to ground distribution.

susanc wrote:Started with 24 grind size, then 20, then 16 before I got it right. The following day, I started with 16, then 20, then 24 before I got it right... Why is this? Can't be the beans... cuz I used the same beans on my Barista Express and got it right the first time.

As a rule of thumb, I always pull 2 shots before making a grind adjustment on built-in grinders. The reason being that the path from burrs to portafilter is almost always significantly longer and more prone to accumulating stale ground coffee than a stand-alone grinder. In the case of the Oracle, you've got the fan in the mix, which adds complexity. I may make some big swings when dialing in a new coffee based off of one shot, but I never settle on a certain grind setting being the right grind setting until I get two consecutive good flowing shots in a row. Generally, the second shot will follow whatever trend the last adjustment made. So if you're going from a grind setting that is too coarse and you are satisfied after 2 adjustments that it's just right, a second shot with no adjustment will likely show that the grinder is actually too fine. My strategy is then to back it off a bit for the next session and walk away.

Getting it right on the Barista Express the first time is great, but not necessarily indicative of a problem with the Oracle. It could just be luck. Did you pull multiple shots on the BE?

I have found myself in more than one vicious grind setting cycle when I tried to react too fast. Invariably, you get a chute full of the last grind size that fills the bottom of the PF followed by the new grind setting on top. If this half-and-half shot pulls too fast, you tighten it up. Then see how the next shot performs, which is also a half-and-half shot. Too coarse mixed with too fine pulls just right and you're happy until next morning when the too fine grounds are stale in the chute. Then you get stale beans mixed with too fine fresh beans and all bets are off as to what ends up in the cup. The second shot tells you all you need to know. The hope is that the first shot is at least drinkable so you can keep the waste low

At any rate. My point is that you need to either pull two shots and base grind adjustments off the second shot only, or figure out just how much ground coffee is trapped between the burrs and the portafilter in your Oracle and purge that stuff out before you make a judgment call on grind size and/or overall machine reliability. If you go the two-shot method, you need to pull two shots at each grind setting to really know. This is very wasteful at first until you get a given coffee dialed in and then can make snap decisions on minor grind changes from cup to cup.

As far as figuring out the chute retention, I like to use a light and a dark roast to find out like so:
•Whatever your normal roast is, pick up some beans roasted WAY differently so you can SEE the difference in the ground coffee.
•Empty your hopper from whatever beans are in there and grind till nothing goes into the portafilter. Don't try anything fancy to get any more grinds out; you want it left as you would leave it when making a grind adjistment.
•Load up the hopper with enough beans for a few shots.
•Here comes the tricky part on an Oracle, grind just a little bit at a time into the PF, checking the color of the ground coffee coming out of your machine.
•Stop when you see the new coffee just start to show up.
•Empty the ground coffee from your portafilter and see how much of the old coffee is in it after you ran the hopper empty.

This amount is how much coffee makes it into your portafilter at the old grind setting every time you make an adjustment, because it has already been ground. This is also the amount of coffee that is stale in your portafilter every morning when you start a grind session. With the Barista Express, I've seen as much as 8 grams retained in the chute. I haven't tried the Oracle, but something tells me it's comparable. Your choice is to either deal with this retantion by living with it and understanding that your first shot will flow fast and changes in grind will be delayed, or purge it. Hope this helps,

Cheers!

- Jake

Hi Mrjag.

The output was either too much or too little hence why we had to adjust the grind size. What is strange is from 24-20-16 on Friday night, to 16-20-24 on Saturday morning just to get it right. Then when we tried the same beans on the Barista Express, using same beans the following day, we get it right the first go! Am starting to regret why I bought the Oracle.

Hi aecletec

Re Barista Express I just use the grinder of the machine. Once in a while, but very very seldom, I would pull a bad shot that needs me to adjust grind size. I always use 18g to pull double shot, so each espresso cup output is 30.

Really think the Express is a better machine especially with the indicator dial...

Thanks so much Jake.

That makes sense. So let met try with cheaper beans to purge the machine of old beans till empty. Then when all is clean I use the good beans. However just a thought, I measure 18g for both oracle and Barista Express each time I pull a shot.

Do u tend to agree then that it's the beans not the machine?

Maybe a silly question, but are you using pressurized or nonpressurized baskets on the Express/Oracle?

For the Barista Express - using pressurized

For the Oracle - non pressurized.

I think that is the key difference then. The pressurized basket will cover up grinding inconsistencies while the non-pressurized basket is very revealing. Try using a pressurized basket in the Oracle to confirm.

+1

Pressurized basket will cover a multitude of sins, but will never compete with a standard basket when it comes to flavor. Shot time will be very consistent but flavor will suffer. I think grind retention is very likely contributing to the issue. Even if you get a consistent dose in terms of weight in the basket, you still have the issue of 30-40% of that dose being ground during the previous shot. Not an issue for back to back shots but treacherous for dialing in and confusing when the first shot of the morning flows too fast.

Have you run the grinder empty with old beans yet? Can you see the difference in the grind a between the new and old beans? This is critical. I suspect it will be 8g or more of old before the new shows up but I haven't had first hand experience with the Oracle.

Cheers!

- Jake

Using the non-pressurized basket first, we started grind size at 30, and I got a good shot at 30 sec, but a bit acidic.

Using the pressurized basket, started at 30, got a good shot at 30 sec, with no acid.

Since I was using older beans, I tried switching to grind 24 but the flow was not even. The right spout was flowing much faster than the left. Taste, just ok.

Then tried 24, 26, 28 still fast flow on right. Taste just ok.

Tried 30 again... right spout just a bit faster than left. Taste just ok...

So now I switch back to non pressurized at 30. Kept the last cup from the pressurized 30 so I can check taste difference. Yes marked difference with the non-pressurized basket, and a drier puck. And the flow from the two spouts are even.

By the way my Oracle only came with non-pressurized basket. But was able to buy dual wall basket 58mm from Breville. When I checked with amazon though they said this basket will not work with 980XL. So I guess that's why I get uneven flow?

My conclusion then is to get a better tasting cup, use the no -pressurized basket, but be prepared to dial in the grinder, and perhaps throw a way a few cups before enjoying your first good cup. Is this the right conclusion?

Appreciate all the inputs from fellow home-baristas. Thanks so much.