Wipeout! (Or; learning to surf the unexpected temperature waves of the BZ09)

Kelsey

I've made my first initial steps into the world of temperature surfing. It's made me wonder if the eBay listing (rather than the manual) was right all along - does this thing have a 1.5 litre boiler, not a 500ml?

It seems to take a very long time of running the grouphead to get the boiler light to come back on again. I should've timed it, but it feels like forever.

Once the light went off again, I started counting. 1001, 1002, 1003, 1000 and.... 'honey, can you grab the milk please?'.... I really should've used a timer. Nevertheless I soldiered on and about 30-45 secs after the light went off, pulled a shot.

It was a little hotter than warm, but not hot by any means.

What I'd really like to do is develop a testing procedure (that preferably doesn't involve drinking 19 coffees in a row) that can help me come to grips with the temperature cycle of this machine.

What should I be taking note of and what should I be timing?
What should I be adjusting at every testing cycle?

Koffee_Kosmo

I have a sage bit of advice Learning how to use a new coffee machine is no different to changing cars They all have a particular way to be operated to achieve optimum results This takes a little time I have very little hands on experience with single boiler machines, but i advise you to slowly work within its limits and anything is possible KK

Kelsey

Yep, that's the plan - I need to find the time to pull lots and lots of blank shots through the machine, probably with a timer, so I can fully understand the way the boiler/thermostat works.

UNM

Kelsey wrote:

Yep, that's the plan - I need to find the time to pull lots and lots of blank shots through the machine, probably with a timer, so I can fully understand the way the boiler/thermostat works.

Most mobile phones have a stopwatch function these days. Even my el-cheapo nokia had one. Probably the easiest way to start timing more accurately. Never did learn to temp surf my gaggia - went pretty much straight to the PID when I got it working after a multi year hiatus. I did, however, check what the PID displayed by way of thermostat on/off temps before wiring in the relay for the heater. That let me get a starting point to get close to a shot temp I liked. I don't think you should cover ALL possibilities, too much wasted time and coffee. Just a suggestion, but might be easiest to decide if you are going to start the shot with boiler heat on or off, then work from there rather than trying to nail both. Let everything sit nice and idle, get a feel for how long the on/off cycle is and try shots immediately the light goes off (or on), 25% of the time to switch, 50%, 75% and 100%, with plenty of stabilising time in between. Should give some indication of where to concentrate on fine tuning your times. You may of course find temp is not that critical, but I found it made a huge difference (although as said before, the boiler in my m/c is tiny).

Kelsey

I think that pretty much covers what I planned to do, although it does seem to take quite a while for the light to come back on, on its own. The testing protocol I'm thinking of requires a milk thermometer and my iPhone. I'll turn the machine on and wait at least 30 minutes for it to get thoroughly warmed up. The manual says 8 mins, but even with the heated group-head I'm not sure I believe it yet. While it would probably be good to get a sense for the natural rhythm of the machine, I'm not that patient! Instead I'll time how long it takes me running water through the group-head for the boiler light to come on. When the light goes out, I'll pull about 60ml through the group and measure the temp. Then I'll run the group again until the light comes on. From then on I'll time increasing 30 second intervals from when the light goes put, pull water through the group, measure the temp and then run water again until the light comes on. When I hit the highest temperature, that's probably going to be optimal. Sound reasonable?

Kelsey

I stuffed up my first shot of the morning and as my wife was still abed and the little 'un was happily chomping away in the kitchen it was time for experimentation. The machine is usually on for at least an hour before use - between 'first cry' and 'time to run around on mummy and daddy's heads'. My first observation is that it takes 500ml run through the group to get the boiler light to turn on again. Given that the boiler itself is supposed to be 500ml, this seems odd. Anyone care to comment? As mentioned elsewhere this machine has heating elements in the group that's supposed to help maintain thermal stability. I think it works - to a degree. The first shots I pulled had a much wider band of temperature range than after a few rounds of testing. Note also that I don't care about absolute temps - by the time it hits the cup there are so many other factors at play to make the numbers meaningless. I just care about the relative temps. For example - 0 secs and 45 secs were the first two shots I pulled - they measured 70c and 74c respectively. After this however I never got a shot under 79c and most were between 80 and 82: SECONDS TEMP 0 80 15 79 20 81 25 82 30 82 40 83 45 82 Random temps taken after having to deal with other things for a a minute or two consistently read at 79. It seems like cycling the boiler at least once prior to making a coffee is a good plan. Which also probably means I can forgo the hour's warm up. Anecdotally, we also had our first dinner guests last night since getting the machine. They were all milky coffees, so making the shots after texturing the milk meant that the temps were pretty spot on.

Brett_H

Looking at this mate I'd start worrying less about temps, times and boilers and just focus on enjoying great coffee from a great machine. Bezzera have been doing this a long time and I'd be inclined to think that the hard work of temp stability and pressure profile has been done for you. It's a great machine... Get out there and roast some great coffee to run through it and when you win lotto install a Slayer, 4 RoburEs, invite us all around and offer us cups of tea made with the Breville jug thingy that makes temperature stable tea ;D... Just because you can! Less thinkiN' more drinkin'...oops,remember when we lived by that motto at Uni... Those days are gone 🙁

Kelsey

I plan to! I certainly don't feel inclined to perpetually sit with a stopwatch to make my coffee - I just wanted an understanding of why I was pulling the odd 'cold' shot. Now that I know, I know that the machine is stable but I need to make sure it's had a shot or two pulled through it before using it and to wait a little while after the light's gone off. Those days are only behind us if we restrict the "drinkin'" part to alcohol. Coffee, wine spritzers, we're all good. 😉

Kelsey

Chris is away until November, at which point I'll be going away too. So mid November we'll hopefully be able to sort it out. At least I'm not the poor SOB on the other forum who ordered his off eBay. His BZ arrived with its guts spilling out the bottom. Couriers dropped it.

Brett_H

Kelsey wrote:

Chris is away until November, at which point I'll be going away too. So mid November we'll hopefully be able to sort it out. At least I'm not the poor SOB on the other forum who ordered his off eBay. His BZ arrived with its guts spilling out the bottom. Couriers dropped it.

Sometimes I think writing FRAGILE on a box is actually interpreted by Couriers as FOOTBALL. The poor buggar... Hopefully when Chris returns he'll have some Lever news in regards to a non-vibe version of the Stratega, although the Domus with two gauges looks UBER cool.... or I can just shut up and be happy.

Kelsey

Or you could put your increasingly impressive handyman skills towards a rebuild.... 😉

askthecoffeeguy

If I'm temperature surfing I generally run some water through my machine, wait for the water refil on the boiler to engage, then run my shot - but personally I think tamp and grind are equally important when it comes to getting the best out of your extraction 🙂

Kelsey

Agreed, CoffeeGuy. That's also an area I'm working on. The naked PF helps a lot and I'm finding just how vast a difference in grind is required bean to bean.

coffeehorse

I think if your temperatures are accurate you need to turn the boiler pressure up a few nibbles. 1) The milk thermometer is a rubbish way to read this. They're not designed to be accurate. Time to invest in a proper temp probe 2) Think about how you're draining the non-heated water (cooling in the pipes) at 15 seconds in and the machine is then returning to rough thermal equilibrium Are the shots good? Sounds like you may be overthinking it - it's not burning the coffee and cool shots are probably a result of over/random-flushing or boiler cycling cycling from too low a temp. That's if you're diagnosing the shots correctly.

Kelsey

Yeah, that's pretty much why I added in a caveat - I wasn't really looking at absolute temps. When the coffee's hot, it's not scalded and it's very very good. I just needed to figure out why I was pulling the odd cold shot - and I'm new enough to the world of single boilers that I needed to understand how my machine in particular functions. So I definitely wouldn't take those temps as accurate! 😃 What they've given me is an understanding of how temperature ebbs and flows in the machine - and now I know that provided the machine's been flushed a couple of times (pretty much irrespective of how long it's been on) anything longer than 20 seconds after the boiler light goes out will give me a good shot - temperature wise at least. I'm making a bunch of other mistakes, but at least it's hot enough!! ;D Did anyone have a think about whether it seemed reasonable that it would take 500ml of water through the grouphead to get a 500ml boiler to turn on? Or is it more likely that the manual's wrong and the boiler is 1.5L as a couple of sites and the eBay listing claim?

Brett_H

I looked at the Bezzera site and they have the specs listed at 0.5l but I always thought they were 1.5l. Pop the cover and take a look. You should even be able to see it with the tank cover off.

Kelsey

I think I might just do that - when Jus is out of the house. Her words - "You are not modding our new espresso machine". ;D Bezzera list it as .5L, Chris' eBay listing had it at 1.5L, other Italian sites put it at 1.5L, the manual puts it at .5L. It's half again as deep as a Silvia. Surely that room's gotta be put to some use!

Kelsey

What an excellent idea! Now I just need to develop a non-coffee vice that's worth hiding. 8) True, true - but I suspect dirty looks would be cast my way if I even came near Betsy with a toolkit... 😃