Hey folks, So I got myself a Breville "The Infuser" aka model BES 840. I bought it in September 2020 and due to being away for work has seen what I would call light but regular usage. Since I have owned it I have observed that when I make two consecutive cups of coffee (or one and leave the machine on and make one an hour or two later) that the extraction results vary wildly (and not well) for my second shot. Same dosing, same tamping, same grind, same beans but different result. What happens is the second shot invariably over extracts - to the point that I won't use the shot. Repeating the exercise only produces worse results. I not a novice and have multiple years if experience on a range of commercial machines so am confident that the variable isn't me or my techniques. I ran a pressure test as prescribed by Breville and it performed okay. The only variable I can think if is that the machine is hotter for the second shot. Or could it be the inverse - cooler thus under pressured for the first shot and I have my grind adjusted for that? The only thing to counter that theory is that I have to coarsen my grind to a less than reasonable consistency if I want a decent extraction for shot #2. Your contributions to my less than happy coffee making situation appreciated. Joanne
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Hi Joanne, the first thing I would do is check that it's not old grinds retained in the grinder. Might sound strange, but ithey will go sufficiently stale overnight to make this kind of a difference, especially if your grinder has a reasonable amount of retention. The first shot has a mix of the older grinds and fresh, while the second and subsequent will be all fresh grinds.
Try purging the grinder for a few seconds before your first shot so that you are using only fresh grinds, then make a second one and see if there is much difference. If there isn't you've found your culprit and can adjust your routine to suit.
If you already purge and this isn't an issue, hopefully someone more familiar with the Breville's may be able to assist.
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Agree with witherz.
You didn't mention what grinder you're using, but it's customary for many on demand grinders (ie not single dosing or low retention) that you purge a few grams in the morning to avoid the "morning gusher". The stale grinds will cause the first shot of the morning to be much faster than the shots for the rest of the day.
This is also necessary when changing grind size. You need to purge the grinder as it will still be retaining grinds at the "old" setting.
Depending on the grinder, it could be anywhere from 1-2 grams or as much as 6-7 grams!
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Hmm.
When you say the 2nd shot over-extracts are you talking purely the taste or is the shot running very slow? Are you achieving roughly the same recipe on both shots (input weight/output weight/time)?
If so then I think it might point to temperature. I looked up that machine and it does have PID control so it should be fairly stable (if it's not faulty). What's the machine's temperature currently set to?
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The shot runs very slow. Machine is set at default temperature not sure what that is? I'm confident inputs are the same, at least what I am controlling vs the machine. I haven't however measured the difference in the output and will do that...at a guess though I would say output volume is reduced in the second shot. A bit short on beans to experiment right now and under lockdown at the moment so getting more is a challenge, but I will measure outputs tomorrow morning and report back. Ta!
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Yeah that's a prety big difference. Generally you'll want to weigh the shots as volume isn't the most accurate way to measure...but even then an extra 20s is significant.
It's extremely unlikely the machine temperature would cause this. Either the machine is doing some crazy stuff, or it's the grinder. What grinder are you using?
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My BES840 doesn't do anything like this, that doesn't seem normal
I've run 3 consecutive shots and weighed each one coming in at ± 5g of each other and very similar times
Ignoring the machine for a minute because you've said pressure tests were fine
Like Tronn asks, what grinder are you using?
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Have you removed and cleaned the burrs in the grinder? Generally you'd need to remove the top burr and clean it with a brush, then clean the bottom burr chamber with a brush and ideally a vacuum with a brush attachment.
With the grinder being 7 years old, the burrs may be blunt which could be why you're getting inconsistant results. If this is the case it's probably not economically viable to replace the burrs, and you'd be better off getting a new grinder.
This is all speculation though. The only way to be sure would be to see if you can borrow a grinder from a friend that you know works well.
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Interesting thought about the grinder, thank you. I have never removed the burrs, will have to do some research on that. To be fair the grinder has a fair few years in it and a LOT of use! I will investigate and report back in due course! I have no friends nearby with decent grinders so may have to splash out on a replacement.
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I’ve owned a few Sunbeam grinders and I can tell you that the burrs on a 7 year old, well used one will be completely shot. You can buy replacement burrs for them but they’re about $80 so it’s not a very economical. Still cheaper than a new grinder so worth considering, but if I were you I’d take it as the universe’s way of telling you it’s time to upgrade to a nicer grinder.Originally posted by joanneebell View PostInteresting thought about the grinder, thank you. I have never removed the burrs, will have to do some research on that. To be fair the grinder has a fair few years in it and a LOT of use! I will investigate and report back in due course! I have no friends nearby with decent grinders so may have to splash out on a replacement.
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