I’m using profitec drive with niche duo, 18g vst basket. Not with every beans but most of them I’m getting unpleasant harshness, bitterness. I know coffee is bitter but unpleasant. After adjusting grind setting when I start getting some sweetness then there is still that harsh bitter aftertaste. I’ve been using different roasters, adjusting temperature, ratio by 5 ml and still, again some beans I’m getting great results but with so many of them , and currently red brick I’m just not sure how to get it of that unpleasant taste.

@"MuddyOne"#p74438 Red Bricks is by Square Miles, right? What’s your typical ratio and shot time of your espresso? I have never used a VST basket. IIRC, @"Cuprajake"#144 have had VST baskets on his Bianca before. Water, Water temperature, grind settings, puck prep can be a contributing factor. Please load a video of your shot. I am sure we have a few members who use VST baskets. They may be able to assist you after looking at the video.

@"LMSC"#p74440 Maybe I’ll try with stock basket, yes red brick is by square mile but I had that with different roasters too. My typical starting point is 1:2 then I adjust once I get grind setting and temperature right. But sometimes nothing seems to be helping 🤷🏻♂️ I can post video of shot in couple days as I have couple of maintenance things to do with my drive .

Loose the vst, Temp will be your enemy

Make sure machine is hot, 45 minutes at least. Set temperature to 94C. Leave the flow control alone, fully open. I’m assuming you are using a bottomless porta filter. If not, do that, and work on your prep. Make sure the shot is extracted properly and evenly. Set the pressure to 9 bar (using the screw under the machine).

@"MediumRoastSteam"#p74444 So the machine is set at 11 bar right? I think I remember seeing that somewhere before, why do they ship machine like that? Why do you suggest to leave control vslvd fully open? Profitec says that normal flow is achieved at 1 And 1/4 , I’m asking these questions to have better understanding about your advice.

@"MuddyOne"#p74455 - judging by your comments, you need to diagnose what your shots have an unpleasant harshness and dryness. I’m suggesting you go back to basics and start from a common baseline. I wouldn’t take the manual as gospel. They also tell you to descale the machine, blackflush and never lubricate the cam.

@"MediumRoastSteam"#p74458 you say I shouldn’t be backflushing either?

@"MediumRoastSteam"#p74458 where do I start then ? You said go back to baseline ?

My current “ tactic” is that I pull a shot 1:2 ratio , taste and adjust grind accordingly . Once I find best grind setting then I lock that too and see if adjust ratio helps, if going either way by 5-10ml helps I lock it , if not I get back to 1:2 . After all that is locked I adjust temperature to see if that improves anything. Any advice here then I’m Doing stuff wrong?

if its not all beans then perhaps just crap beans?

I can’t seem to get rid of unpleasant harshness and dryness

MuddyOne

MediumRoastSteam yeah I did , sent that email before Christmas break and they may have forgot about that fact. But I sent them a reminder now with screenshot of that email, and a video I recorded ( I didn’t record first video after 30 minutes)

Basically what we talked is now reflected on devices , I switched machine on , set to 95 put the wire into ports filter and after 30 minutes it showed 95 degrees, plus minus half degree. But after another 30 minutes it showed that :

I sent them this video and explained that 30 minutes after turning on it was showing 95 degrees, now 99.

MediumRoastSteam

MuddyOne - Excellent! I hope they “get it” (i.e.: how can a machine like fluctuate the temperature like that when idle?) - It’s a dual boiler machine, not an HX!

I hope you find resolution and that your retailer sees the problem (rather than pretend everything is just fine). And I hope you don’t hear the usual: “Oh, that’s just perfectly normal. I wouldn’t worry about that. Those machines need a cooling flush after being idle for longer than 30 minutes”. No, no, no. It’s a dual boiler. It should not behave like that.

Good luck.

MuddyOne

MediumRoastSteam

This is the answer I got from them

“The coffee boiler temp will heat up the longer the machine is on, so perhaps best to put the machine in eco mode when not needing it to make coffee, or when not used for longer periods.”

I replied that if machine is not keeping stable temperature that was set then that’s not how pid should work and is certainly malfunctioning.

But setting the offset to minus four helped keep 95 degrees ,I need to wait till tomorrow for machine to cool down now to see if that is the case both after 30 minutes and 1h

MediumRoastSteam

MuddyOne The coffee boiler temp will heat up the longer the machine is on, so perhaps best to put the machine in eco mode when not needing it to make coffee, or when not used for longer periods.”

As predicted.

MediumRoastSteam “Oh, that’s just perfectly normal. I wouldn’t worry about that. Those machines need a cooling flush after being idle for longer than 30 minutes”. No, no, no. It’s a dual boiler. It should not behave like that.

Total nonsense. As Jake said… It’s a dual boiler. One boiler is for brew water (i.e.: Should be kept at brewing temperature at all times) - the other other boiler is for steaming. There’s no reason for the brew boiler to overheat over time - That ’s for a Heat Exchanger machine behaviour.

They are fobbing you off.

Total nonsense.

Cuprajake

Having a dual boiler that doesn’t keep stable temp is pointless, may as well have bought an hx and saved the money.

Bit of a crap answer.

How long does the machine take to heat up.

MuddyOne

Cuprajake i test after 30 minutes and then it shows temperature that was set , after another 30 minutes it charges up again.

I suspect that it’s fully charged after 20-25 minutes already.

Adrianmsmith

Cuprajake

@MuddyOne

Agree with Jake. Bad answer from your dealer.

I had a synchronika which isnt that different control wise to what you have and never had any temperature issues

Does the reported temperature change or just the actual.

MuddyOne

Adrianmsmith

Sorry I’m not sure about your question:)

If you set the temperature to x, after 30 minutes it will be x and obviously that’s the time it should take machine to fully charge up already . But after a while it will raise by another 2-4 degrees, can’t say after how much exactly as I test in 30 minutes gaps after turning it on, it may 40, 50 minutes after turning on. No wonder I’ve been experiencing bitter espresso if I was brewing dark roast at 93 degrees thinking it’s 88-89 or medium at 97-99 .

Adrianmsmith

MuddyOne

Does the pid still show the set temperature or does that change as well.

Is it just that actual water that is hotter then what the machine says it is

Ie is it something along the lines of faulty relay or faulty control logic

MuddyOne

Adrianmsmith well I will run more tests in following days now that I have this device but, last test it went up to 95 degrees with off set now -4 , but after 10-15 s dropped to 90 I wanted to actually ask if that how it should look like, I understand that flushing drops temp , but that also means that after few seconds we are not brewing at regular temperature.

I will run more tests tomorrow.

Adrianmsmith

MuddyOne

The offset is not time dependant.

Its just a “fudge” because the temperature probe is not at the point where you want the set temp to be correct.

It should not be used to vary the temperature over time as you require

To find out what is happening we need more info.

I.e is the heater relay doing as it is told by a faulty control circuit or logic or is it closing when it should not and heating when it should not.

Need to check the pid temp, the set point as well as the actual water temp at the time periods you have issues with .

Now you have elaborated what’s happening, offset is not your issue

MuddyOne

Adrianmsmith yeah I think something is wrong with the machine and it’s not offset , look I set off set to minus 3 and turned on machine (it started heating up from 25 degrees since last time I turned it on) after 25 minutes it reached only 84 degrees, then pid showed it dropped to 79 degrees in 30 seconds.

Second video I tested after 1h of turning it on, it reached 93-94 degrees but not 95 , something is wrong with the pid here:(

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