Post By chokkidog
Post By Dimal
Post By Jaya
Isomac Millenium tastes bad
I purchased a 2nd hand Isomac Millenium (gen2) a few months or so ago for my father (I own a VBM super) as he previously had an auto machine and wanted better coffee (like what I make on my VBM).
The machine was about 5 years old and had just had a $700 repair/service job done. I bought a 2nd hand Macap M2M to match it along with required accessories.
After buying it I did a full flush for him and got it setup I showed him how to use it and left him to it.
Turns out hes hardly used it because his coffees always tastes I think bitter and I offered to take a look.
I did a few shots and dialled in his grind which had been very coarse as he thought the bitterness was from over extraction.
I also removed the shower screen and cleaned it. It wasn't too bad but I hadn't done that after purchasing, only a back flush.
In any case the coffees were better but still bitter and I am not sure what the problem is. I can guarantee the grinder is spot on and the beans fresh - the pour is great and looks OK.
This takes me back to either there being some old stale grinds somewhere (though it had been serviced and I had backflushed) or the brew temperature is too hot.
What are peoples recommendations? I said to check the brew temp with a thermometer in a pre-warmed cup, though that won't be entirely accurate.
We don't make taking it to a shop or pay someone to look at it and get it sorted - he just wants a good coffee because at this stage its been a waste of money.
You say his grind setting was coarse..... that won't lead to bitterness but it will give sour coffee.
You don't provide any extraction details either. Dose weight, extraction time and yield. Even if you don't want to get geeky about the tech side of extraction you should have a
set of standard parameters to which you base your everyday coffee on. If the machine was serviced by a reputable technician there will be nothing wrong with it; i.e. don't blame the tools.
What do you mean that the grinder is 'spot on'?
If the machine is an older model it will need a cooling flush of a few seconds, through the group, prior to making the first shot after the machine has been idle. This is standard practise for these machines, if required, and not a fault.
More information is needed to make better comments and a description of your whole modus operandi, rather than an assumption that it's the fault of the machine, will help.
Just another point to add to Chokki's excellent suggestions, did you strip down the top end of the M2M before you let your Dad loose on it? A collection of stale grinds and oils inside the grinder won't help matters...
Hello thanks for the replies.
Yes he was changing the grind more and more coarse to remove the bitterness.
The process is the same as what I do with my VBM which is why I didn't go into that detail. They are both HX machines so my process should not need to change.
It's a 15g VST basket and getting ~60ml coffee in ~25 seconds. When I say the grind is spot on I mean it is not too coarse or too fine, giving an ideal extraction.
Yes the machine was repaired and I believe serviced as part of that (I would need to check the invoice) and I haven't blamed anything yet, I am trying to determine what the cause is.
I did not mention but I did perform cooling flushes prior to each shot.
I have not stripped the grinder down but I believe my father has. Either way its done a fair few grinds, I would not expect it to cause this issue. My grinder is several years old and I have never needed to strip it out and clean it and its never affected the taste badly. The M2M has very low grind retention and we had grounds a few coffees so there won't be any week old stale grinds coming out.
What if you tried your grinder with his machine/ his grinder with your machine so that you can isolate if it's a machine or grinder issue?
Also as chokkidog says, ideally you would have a weighed dose/ yield (in grams rather than ml's) as a reference point
Hello Jaya. Yes I was thinking swapping grinders would isolate that as the cause so I think that will be my next step.
Also I notice that this Millenium doesn't have a pre-infusion step on the brew - It's an E61 and so the lever has the half-way point for pre-infusion but with the lever in that half-way position it does not activate the pump.
Is this normal for the Millenium or has someone perhaps replaced the switch?