Steaming is not what a SBDU machine good at as far as I'm concerned, speak for my self I picked such type machine because I only drink straight espressos. If I were doing a lot milk drinks, I would go for a dual-boiler, or add a stovetop steamer. Just my 2 cents.

I have 2x SBDU machines, so effectively it's a dual-boiler setup

It would be interesting to test the steam dryness of various machines. I think it would be fairly easy to test using water. Take say, 5 oz (142 g) of water at refrigerator temp (approx. 40º F), purge the wand, and heat the water to 140ºF. Then weigh the water again. For more accuracy you could do 3 times and average the results.

Anyone wanna take their chances against by lowly BDB?

I have a Saeco SIN 006 / aka Starbucks Barista (single boiler) and a commercial LaCimbali M32 Bistro single group (dual boiler).
I just tested the two side by side, took 270g of ice water (170g of ice) starting at 0°c, purged initial water from the steam wand and heated to 70°C. both ended with comparable mass of added water, gained about 60g.

actual results,
saeco - 398g to 452g including 130g ss cup; 32f to 155f (0c to 68c); 5 minutes

lacimbali - 398g to 460g including 130g ss cup; 32f to 168f (0c to 76c) <1min

For reference, the initial purge on my saeco was 26g of water, but some of that may have been leftover water from brewing. The LaCimbali had only 5g to purge. Also it took forever on the little saeco and the vibrations sounded like a banshee getting tortured shortly after the ice melted. Anyone else do any experimenting?

seaneyo, I'm not sure I understand how ice water and water at 70°C are relevant for testing steam dryness. Wouldn't you want to test this at steaming temperature (e.g. 120°C)?

boren wrote:Thanks for all the replies, but I don't think boiler temperature has much to do with the difference. My Quick Mill produces roughly the same amount of water when I steam at 120c and at 135c. In both cases it's about 100 ml of water that I need to purge or it all goes into the milk.

With the MCaL on the other hand the machine is set to 1.0 bar (equivalent to about 120c) and there's hardly any water in the steam. It's a good thing I don't have to rely on the Quick Mill for steaming. I guess it's a nice backup if my MCaL needs to be serviced, but definitely not something that can be considered a good feature (not to mention the 2 minute wait time between brewing and steaming).

Could it be because cold water has remained in the tube from previous uses? It happens to my Rancilio Silvia too. What I do is purge some seconds before steaming.

boren wrote:seaneyo, I'm not sure I understand how ice water and water at 70°C are relevant for testing steam dryness. Wouldn't you want to test this at steaming temperature (e.g. 120°C)?

The steam is certainly above 100C throughout the process (unless it condenses in the wand, like during purging), but the milk is going from ~0 to ~70C. If the dryness is measured as the amount of g or mL of water added to the milk during the steaming process, I used ice water to increase the total amount of heat required to transfer to the milk to see if there was more mL water added per Joule of heat transferred to the milk for the small consumer machine vs the big commercial machine, in case the difference was too small to measure in 270mL of milk.

I suspect that the large difference in purge is a combination of variables, but notably that the small machine has very narrow steam wand plumbing, the boiler is tiny and does not heat up as much of the plumbing during warmup. The commercial machine has larger plumbing which conducts heat more effectively, the whole machine and chassis heats up due to the large boilers, so less steam condenses on the inside of the steam wand plumbing because
-the plumbing is hotter in the laCimbali before initial steaming than in the Saeco
-the steam has more cross sectional area per unit circumference of the inside of the wand, making the plumbing to the wand a less efficient heatsink, which in this context makes it dryer until the wand plumbing is heated above 100c.

however, the Saeco takes much less time to brew the initial cup after being turned on in the morning, if neither machine is on a timer, so... depends on what you're going for I suppose!