# My first ok shot what do you think?



## stevenh (May 15, 2014)

Right so after going through loads of beans I think I've got the grinder set in the ballpark... Maybe a bit too fine will try again tomorrow...

My observations:

Using a single basket was easier to work with to diagnose as didn't waste as much beans...

The ground I got from coffee shop wasn't fine enough, using a bottomless it just sprayed all over pretty messy. Tamp looked good... Fortunately only got them to ground half the bag...

Using the beans and the Mazzer SJ to grind first shot took forever, way too fine... When it came out was smooth with no sprits so tamping wasn't too bad...

After adjusting got 9g in 26g out in 30secs, went over a bit...

After sitting for a while it became 14g?

For the final run used double basket... 16g in 42g out in 30secs, see pics:



























































Any comments apart from the crap latte art?

The pressure gauge is always reading quite high so the brew group is always full of steam so need to flush before each brew, is this normal? I only leave for a few minutes while I prepare stuff then try a flush and need to run for 5-10secs before steady run of hot water?


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## Mrboots2u (May 10, 2013)

If you move between single and double baskets you will have to adjust the grind. I've never got on with single baskets particularly , find harder to dose and tamp and extract .

I suppose the real question is how was the taste ? Balanced ? I'm am unsure why the weight of the shot would change that drastically over a short period of time though .

16g into 42 is a longish shot but again not wrong if it tastes balanced to you ...

Enjoy


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## stevenh (May 15, 2014)

Yeh I ran it a bit too long so taste was quite bland not balanced enough...

Will be trying again this morning hopefully with better success...

Used the single basket just to get into rough ballpark and practice tamping to see if getting any channeling with the bottomless portafilter apart from first one all others looked good... Won't be using single basket anymore once got the double working nicely


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## Mrboots2u (May 10, 2013)

Only my experience and not with your machine but I found it easier to stick to a double basket for prep and distribution . Try moving the grind finer and got to 16> 32 g . Taste then try moving it shorter and see which one you prefer ...

Good luck and enjoy


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## jeebsy (May 5, 2013)

Single baskets are rarely used on here, they're a bit of a pain in the arse generally. Stick with your double


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## stevenh (May 15, 2014)

Exactly what I was going to try today









Thanks!


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## stevenh (May 15, 2014)

The single basket was mainly due to running low on beans to play with lol


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## stevenh (May 15, 2014)

Oh and regarding the weight change. Think might be due to my scales being a bit temperature sensitive? Going to try putting a placemat or something on it to insulate see if that's better...


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## Mrboots2u (May 10, 2013)

stevenh said:


> Oh and regarding the weight change. Think might be due to my scales being a bit temperature sensitive? Going to try putting a placemat or something on it to insulate see if that's better...


Dunno to be honest ,i never leave mine long enough on a scale to notice . Seems like a lot to drop in weight but could be talking out of my bottom again ....


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## stevenh (May 15, 2014)

Will put a small shot of boiling water on it see how much it changes...


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## stevenh (May 15, 2014)

Quick experiment shows that my scales don't do too well if hot things left on it too long but had a small rubber tamp mat on it and then was fine









Waiting for my unit to fully heat up just now as found that even though reached temperature and the brew water is flash boiling but the actual water temp when it starts to run is under 80C so think the group head still need to heat up fully...


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## stevenh (May 15, 2014)

Actually the brew temperature never gone above 75C is that right? I put a cup directly under group head and had thermometer in.... the hot water temp is about 80C as well...

These sound about right?


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## CoffeeJohnny (Feb 28, 2011)

Have you calibrated your thermometer? Also are the cups cold?


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## DavecUK (Aug 6, 2013)

stevenh said:


> Actually the brew temperature never gone above 75C is that right? I put a cup directly under group head and had thermometer in.... the hot water temp is about 80C as well...
> 
> These sound about right?


If you put a cup directly under the group and the hot water is around 80C, you're probably about right on brew temp....you will be surprised what it loses as it fall into the cup.


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## stevenh (May 15, 2014)

Out the kettle it reads about 95C...


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## stevenh (May 15, 2014)

Also tried letting the water run directly over thermometer... Everything was heated up...


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## Kyle548 (Jan 24, 2013)

stevenh said:


> Quick experiment shows that my scales don't do too well if hot things left on it too long but had a small rubber tamp mat on it and then was fine
> 
> 
> 
> ...


Scales work by passing a current though a metal bar and then timing how long it takes to come back.

In simple terms, they ping your drink. If you make the metal bar hot, then it's electrical resistance changes (thermometers work in exactly the same way) and the 'ping' will return differently.

Thus, with a different reading.

To be fair, thermometers usually use two different metals and judge the change in conductivity between the two, but it's a similar idea.


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## stevenh (May 15, 2014)

Ok now 6 weeks later after a lot of repairs and upgrades etc the machine is finally in top condition!

I replaced the crappy plastic retention valve which was not exactly retaining (the plastic bit inside had split) which meant the heat exchanger was not able to maintain pressure.

The result of that is when brewing it takes 10+ seconds to build up pressure so trying to time anything from when the pump starts is useless...

What it also means is that there is massive excess of steam from the brew head... Ppl thought it was just steam as part of the cooling flush but it's because the hx is low on water and pressure...

Finally since it is a mixer type setup, the shots are too cold due to lack of hot water in the hx to mix with and so the shots are a bit more towards sour side...

The fix for this was to either replace the plastic bit which may fail again at some point or replace the whole retention valve with a full metal type which is what I did...

Bit of a patch job setup here but wanted to avoid unscrewing too many pipes to shift the boiler for more room (otherwise tee should go straight on to the shiny silver retaining valve...










I also replaced the pump because I thought the flow rate was a bit low... Turned out pump was fine and the low flow rate was due to a restrictor on the inlet of the OPV which was added since last year to quieten the machine down a bit... Oh well got spare pump now









After all this, made an Italian Job flat white and it tasted so much better than before... 2nd shot hit 16g/30g/28s.

So if anyone else experience strange issues with cold shots and long time to build pressure for initial drops to come out then check the retention valve... Only for HX type machines probably...


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## jeebsy (May 5, 2013)

What machine is this? Not your Oscar?


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## stevenh (May 15, 2014)

It's the Musica though a lot of the internals is same as Oscar.


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## jeebsy (May 5, 2013)

Thought it looked a bit familiar. It's a shame you've had so many issues with it


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## stevenh (May 15, 2014)

It's all part of learning... Think I know a lot more about the machine now









At least now I think I'm pretty confident I can fix any other issues that occurs but just now it runs nicely


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