# Small boilers



## Peelie72 (Jan 10, 2011)

The Silvia & other machines such as the new Piccino have boilers the size of a coke can.

As I understand, this boiler is constantly topped up.

If this is the case, I feel that the temp stability can only be maintained when there is no demand.

As soon as one pulls a shot, the temp must drop quite quickly with cold water entering such a small boiler.

Or are there any other systems within these machines to counteract this effect?

I notice from a temp graph of a PID supply company that their PID Silvia boiler temp still plummeted under demand.

Guess this is why the Isomac Zaffiro has a large boiler.


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## DonRJ (Apr 3, 2010)

There is no way of preventing some temperature drop when you pull a shot, a bigger boiler will of course reduce this due to the greater thermal mass but you can mimimise the effect with smaller boilered machines by making sure everything is up to temperature by preheating for a decent period of time. If you monitor temperature during a shot with the Silvia for example, the drop is not anywhere near the 23c drop shown on one web page I looked at. I will monitor my machine tomorrow morning and feedback the results for temp at start and end of pour.

The smaller boiler effect is an issue of course which is why the bigger semi-pro machines are capable of very consistent shot production, with the Silvia you can get very consistent results but it takes more attention and preparation and an acceptance that you cannot pull shot after shot in quick succession like you can with a big HX.


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## Peelie72 (Jan 10, 2011)

But I guess the HX machines take a while to warm up and use a lot of power.

All this marketing about pouring a shot and steaming the milk simultaneously makes me laugh.

Why on earth would a home barista wish to do such a thing?

I'm starting to wonder why a small double boiler machine is advantageous.

Jesus, selecting a new machine is a minefield!!!!!!!!


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## MonkeyHarris (Dec 3, 2010)

It's certainly not a simple task. You've really got to look at what you need to get out of it and make your purchase based on that. A lot of home baristas (me inlcuded) like the idea of a double boiler. Not really because you can steam and pour at the same time (this would be pretty difficult anyway) but if you have to make several milk based drinks in one go (or more than two) you haven't got to purge the boiler of all steam, then refill and wait for it to heat up before you can pull another shot. I had some family round over Xmas and everyone commented on the lovely lattes etc. I was making but moaned about how long it took to make them. If this isn't something that's going to bother you then I'd say try and go for an E61 HX type machine instead. Although like Don I cannot really fault the Silvias shots. They are the best I've ever tasted. You just need to get the hang of it. I'm not sure what double boiler machines are about that let you heat the boilers seperately. I'd be interested in this as I rarely froth milk anymore anyway.


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## BanishInstant (Oct 12, 2009)

Before I purchased my secondhand HX I was frustrated with the wait between brewing and steaming. I make mostly milk based drinks so this is very important to me. With my HX I can brew coffee and steam milk at the same time. On the odd occasion that my house is invaded by coffee lovers, a big boiler makes light work of the demand.


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## DonRJ (Apr 3, 2010)

All espresso machines need a decent warm up time, what you are paying for with a big HX or dual boiler machine as mentioned is simultaneous brewing and steaming, producing more shots in a row quickly and greater ease in achieving consistent results. Mind you any machine takes time to get the best out of.

I, like Banish make milk based drinks, so in future will move towards an HX machine or if funds allow a dual boiler like the Izzo Duetto. I don`t honestly expect to get markedly better shots than the Silvia at its best, but it will be a lot easier when the family descend to knock out between four and eight lattes or cappas.


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## Peelie72 (Jan 10, 2011)

thanks guys.

i too, as with most coffee drinkers, use the machine for cappuccino/latte style drinks, but i like an espresso once in a while, especially when trying to improve.

i read somewhere that the temp drop (within a permitted range) during the pour can give a wider range of flavors.

one has to wonder if its just a case of obsessing over nothing.

i did read that the expobar dual boiler - steam boiler feeds into the shot boiler. that makes sense to me, though it has to be a more difficult design challenge to cool than to heat.

read somewhere that its better to steam milk first then cool a single boiler for the shot. i feel its better shot first. what do you guys do with sb's?


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## DonRJ (Apr 3, 2010)

I always do shot first, milk second


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## lookseehear (Jul 16, 2010)

Peelie72 said:


> thanks guys.
> 
> i too, as with most coffee drinkers, use the machine for cappuccino/latte style drinks, but i like an espresso once in a while, especially when trying to improve.
> 
> ...


I would always go for shot first too, especially if I'm worried about latte art! Pouring is pretty impossible if the milk has been sat for 30-40 seconds after steaming.

I know that some double boilers pre heat the water entering the brew boiler via a heat exchanger going through the steam boiler, I would be surprised if a steam boiler was actually to feed a brew boiler as the water would be too hot and the higher pressure would make things difficult I imagine!

I'm fairly sure the speedster does this but I'm not sure which others do


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## DonRJ (Apr 3, 2010)

Update on temp drop during a pour.

monitored while making this mornings coffees and the Silvia drops around 2.5c during a 25 second pour. This is measured at the top of the boiler with the thermocouple attached to the top surfac of the boiler near the cold inlet so the actual drop is probably a bit less down at the business end. The addition of a PID would probably reduce this a bit.


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## DonRJ (Apr 3, 2010)

The Izzo Duetto uses this system of preheating the brew boiler water with a heat exchanger running throught the steam boiler. If you have a look at the PDF file for the Duetto or Expobar dual boiler machine on Bella Baristas site there is a diagram of this.


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## BanishInstant (Oct 12, 2009)

With a single boiler I would brew first and steam second. As Don has mentioned, if the machine has been warming up for quite a while, then you have an improved chance of a consistent temperature during a brew.


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## Peelie72 (Jan 10, 2011)

Good point. The pre-heating through a HX is simple but must be very effective.

Now I wonder if the Piccino has a similar set-up?

What I'd give to get my hands on the specs & data of that machine!


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## Grumpy (Jan 21, 2011)

I don't know much about Rancillio silvia's at £639.00 plus vat. However if its a small boiler why use it. I use a Fracino Hevenly from espressounderground.co.uk and it's a semi proffessional machine with proffessional group head and larger boiler more than caperable of keeping up with demand and it's cheaper.

Have a look


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## lookseehear (Jul 16, 2010)

Rancilio Silvias don't cost anywhere near £639.00 plus vat, where did you get that from?! Hasbean do it for £435 inclusive of VAT, Fairfax do it for £475 inclusive of VAT, a huge amount cheaper than a Heavenly from your site.


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## Eyedee (Sep 13, 2010)

I do hope Grumpy is paying the forum for this blatant advertising.


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