Mini owners! Need your help.

Post general questions about operation of your new Mini here. Due to many similarities with the original VII you should also check the VII forum.
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zoey

Mini owners! Need your help.

Post by zoey »

Fellow mini owners, I am wondering if you could check something for me?

1st. Are you running 15 or 20 Amp?

2nd. While steaming milk, what is the lowest pressure your gauge is showing?

3rd. How much milk were you steaming when you read the lowest pressure?

4th. About how many seconds into steaming did you hit the lowest temperature?

Thanks!
Cliff

Re: Mini owners! Need your help.

Post by Cliff »

--20 Amp

---,7

--- about 8 oz.

--- about 8 seconds

Why whats going on?
zoey

Re: Mini owners! Need your help.

Post by zoey »

Well, my machine just putts out before I can get done stretching milk. I was just wondering if it was something with my machine or that I'm on 15amp.

My machine drops below 0.5bar when steaming about 8oz milk.
JohnB

Re: Mini owners! Need your help.

Post by JohnB »

Just for comparison I checked my S1V2 & it took a little over 1 minute to get down to 0.5b.
zoey

Re: Mini owners! Need your help.

Post by zoey »

You've got the 2.5L boiler don't you? I think the Mini is something like 1.2L.

I need to time my machine, but I am pretty sure it drops to 0.5bar well before the minute mark.
JohnB

Re: Mini owners! Need your help.

Post by JohnB »

zoey wrote:You've got the 2.5L boiler don't you? I think the Mini is something like 1.2L.

I need to time my machine, but I am pretty sure it drops to 0.5bar well before the minute mark.
Yup, 1.2l vs 2.5l with the same 1250w heater. Are you flushing the steam wand & letting the boiler recover before steaming? Using whole milk? Does the pressure recover quickly once you stop steaming?
zoey

Re: Mini owners! Need your help.

Post by zoey »

Yes, I'm flushing and allowing for recovery. Yep, whole milk and the pressure does recover fairly quickly after steaming. I will time it next latte I make.
zoey

Re: Mini owners! Need your help.

Post by zoey »

The recovery period after steaming is about 45 seconds. I started thinking a little about it and realized that it's not the recovery time that is problematic. It's that I am losing steam pressure before I finish steaming.

I watched the gauge closely today and it's actually well below 0.5 bar when the milk hits about 115-120F.

I've got the same size heating element as the V2, but only 15Amps to heat it up. In my mind, the same element size heating a smaller boiler should result in an increase in constant pressure as well as a faster recovery time. Unless of course there is some mechanism to cut the heating element out sooner or at a lower temperature.

So I'm wondering if 20Amps would help the heating element to maintain a higher temperature during the steaming process, thus keeping the pressure higher during steaming (less of a dramatic drop in pressure).
Cliff

Re: Mini owners! Need your help.

Post by Cliff »

I timed mine today with no milk just the steam wand opened up all the way. It took just about 45 sec. to get to .5bar. I do have mine setup in 20 amp. but I don't think it should make the kind of difference we are seeing between yours and mine.
JohnB

Re: Mini owners! Need your help.

Post by JohnB »

Zoey - Have you disassembled the assembly between the boiler & steam wand to make sure you haven't got one of those famous brass shavings partially clogging up the works? The 20A will only factor in if both boilers need to run at the same time.
zoey

Re: Mini owners! Need your help.

Post by zoey »

Well Cliff, that's a bit discouraging.

However, I did discover something interesting tonight. Another member here (sorry, don't remember who) told me that I needed to find the "sweet spot" for steaming. Well, I think I found it. I found that I get great turbulence when I point the wand directly down into the milk (90 degree angle) and about 1/2 way between the center of the pitcher and the outer edge. The turbulence change was significant and actually injected too much air into the milk. I'll have to work on it again tomorrow.

No, I haven't. I pulled the tip of the wand off to see if anything (ie metal flakes) had taken up residence. Nothing there.

I will have to add that to my list of things to do when I open it up for the 20Amp conversion. The target date is the 25th (after finals).

I'm going to do some official timing as soon as I get a chance. I'm going to time the steaming process repeatedly along with the recovery times at 15Amps. Then, I'm going to repeat the test at 20Amps.
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BrewHaHa
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Re: Mini owners! Need your help.

Post by BrewHaHa »

JohnB wrote:The 20A will only factor in if both boilers need to run at the same time.
Exactly. In other words, switching to 20A operation doesn't make the steam boiler heat up any faster or any hotter, it simply ensures that the steam boiler element stays on even if the group boiler element comes on. If the group element doesn't come on while steaming, performance will be exactly the same whether the machine is set to 15A or 20A.

My machine (an older S1) is set to 15A, and after I pull a shot I just wait a few seconds for the group boiler to heat back up before steaming the milk. Here's my sequence of events:
1) Flush the group to get it up to temp
2) Once the group boiler is up to temp (and the light stops blinking), start pulling the shot
3) While the shot is flowing, blow off some steam, to flush out water and cause the steam boiler element to cycle on. This will ensure that when I start steaming, the element will already be on, giving me a "running start" at keeping boiler pressure up.
> At some point during the shot being pulled, the steam and group lights will be on at the same time. Since my machine is 15A, only the group element will actually be on. That's okay; see the next step...
4) Shortly after ending the shot, the group boiler will recover (the light will stop blinking), and the steam boiler element will come on
5) Blow off a little more steam to clear any condensation
> The steam boiler light should still be blinking at this point, indicating that the element is on
6) Steam the milk
> Since the group has just recovered recently, I've never had the element go back on while steaming the milk

I realize purists may say that if you steam the milk and pull the shot sequentially instead of simultaneously, that you should steam the milk first. I'm sure you could easily figure out a similar steam-first sequence that allows the steam element to stay on while steaming without being interrupted by the group element.

But all this is to say that if the group element does not come on while you are steaming now, running on 15A, then you shouldn't expect any improvement in steaming by switching to 20A.
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zoey

Re: Mini owners! Need your help.

Post by zoey »

Well, that's a letdown for me.

I've noticed that running back-to-back steaming produced drastically different results. I actually run out of pressure during the first steaming, but the second steaming has plenty of pressure. This is regardless of how long the machine has been turned on.

I've started purging my machine several times, dropping the pressure to about 0.5 bar each time, before actually steaming milk. It improves the pressure a lot when I start steaming the first milk.
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chas
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Re: Mini owners! Need your help.

Post by chas »

The other "cheat" to make your steam pressure last longer is to use a steam tip with smaller and/or fewer holes. Whether that's a viable option to try depends on the quantity of milk you are steaming. Does the Mini ship with the 4 hole tip that has the 0.9mm holes or the one with the 1.2mm holes?
Chas
LM GS/3 & LaSpaziale Dream v 1.25 (US 120V)
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zoey

Re: Mini owners! Need your help.

Post by zoey »

It has the 0.9mm holes. If I'm not mistaken, all of the Mini's come with it as standard.
Niko

Re: Mini owners! Need your help.

Post by Niko »

BrewHaHa wrote: Exactly. In other words, switching to 20A operation doesn't make the steam boiler heat up any faster or any hotter, it simply ensures that the steam boiler element stays on even if the group boiler element comes on. If the group element doesn't come on while steaming, performance will be exactly the same whether the machine is set to 15A or 20A.
Exactly but that still creates another variable.
You can't sit there and hope that group boiler doesn't kick in while you're steaming milk, that's the handicap you're fighting in 15A mode. Especially on a VII and a Mini, the old S1 didn't cycle as much with it's not-so sensitive probes.
The trick to steaming with more power is to keep that element heating through the whole steaming process.

Here's my VII steam cranked all the way open, I had to stand back since the room quickly filled with steam.
Sorry about the cam shake but it was hard to stay out of the line of fire :lol:
http://www.youtube.com/watch?v=1v-uTI9nDdg
You can catch it in the very end of the clip that the boiler never reached below .8 bar.
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