I'm able to make decent Latte art but it seems my microfoam deteriorates very quickly. It starts off looking velvety and smooth, but after about 1 minute, 1/8" macrobubbles start to surface that destroy the look.

Any ideas how to get rid of the these latent macro bubbles for longer lasting, velvety microfoam?

(Drink faster is not an acceptable answer).

From USBC Barista Competition - Competitor Debriefing:

Abe Carmeli wrote:Avoiding Crema Bubbles

Bronwen is famous for her cappuccinos, and here's what makes her shine: Often, a cappa will show crema bubbles. This may not affect the taste so much as it affects the visual. To avoid crema bubbles she drops a little foam to the cup and immediately starts swirling and banging it on the counter as one would do with a steaming pitcher. After she is happy with the result she pours the rest of the milk.


A perfect cappuccino by Bronwen Serna served during the judges certification workshop.

Those are a couple of really nice looking drinks.

I ain't no Bronwen Cerna, but I'm not so sure this has to do with the crema as much as it has to do with how the milk was textured and poured.

I have experienced what Endo is referring to. The milk looks good in the pitcher, it pours nicely, and within a few minutes, sometimes very quickly, it has small or even large bubbles on the surface that destroy the art. Sometimes it happens evenly across the surface, sometimes only at the edge, and sometimes it just outlines the rosetta and the rest of the surface is smooth.

I don't swirl the crema or bang the cup on the counter prior to pouring and I have all but eliminated this issue. I might see it 1 in 10 these days when it used to be more like 50% of the time. I'm not saying what Bronwen does won't help or isn't effective, it is just something I don't do and I was still able to eliminate the issue.

I find when micro foam is stable the art will remain smooth for several minutes. I think this has to do with how aggressively the milk is textured, how long it is incorporated after the bubbles are formed, and what the final temperature is. The more gently I texture and longer I can incorporate the less this issue seems to occur. Of course if I get the milk too hot all bets are off. The milk will still pour but will the art fall apart quickly.

When I begin to pour I try to remain very steady and start with a small stream fairly close to the surface. If I allow the stream to wiggle when I start I notice that bubbles are created at the surface. Or if I glop out the first bit of the stream some bubbles will form around the splash. And if I pour from too high bubbles will be created by the stream as it penetrates the surface.

I think the bubbles all over the surface have to do with the texture of the milk, and the ones that outline the art are more a result of the pour.

Don't over-stretch the milk; swirl milk aggressively in pitcher (after steaming and letting sit for a minute while pulling the shot).

malachi wrote:Don't over-stretch the milk; swirl milk aggressively in pitcher (after steaming and letting sit for a minute while pulling the shot).

Thanks for the advice, I will try this—milk stretching before shot pulling.

Great tips! Thanks guys!

What's the milk fat content? Skim milk often *appears* to foam nicely but the foam breaks down rapidly after being poured. I use 2% for health/weight reasons but get the best, most consistent and most stable (i.e. long lasting) results from whole milk (4%).

I used to have this problem.. Drove me mad when I was learning rosettas.

i use Parmalat, Whole Milk.

i saw a video on Vimeo one time of someone pouring a tulip, and before they poured the art, they took the cup with the espresso in it, and swirled it around, putting crema about 3/4 of way up the cups walls. Then poured the art. First time i saw this, I thought they were nuts, breaking up the beautiful cream like that. But eventually, I tried it. I dont get bubbles anymore. But, while I think that does help, i think it has more to do with how the milk was textured. I was having trouble getting superb milk with the stock, 2-hole tip that came with Anita. Good milk was commonplace, textbook milk was not. So I cheated, and bought the expobar single hole tip. It takes a bit longer to finish the milk, but the result is the shiniest white chrome and the sweetest taste ever*. Not a single bubble. I stretch very gently too 100F, and texture to 155F.

*the single hole tip does make some awesome microfoam, but I have never have sweeter, creamier milk then when I used a borrowed four-hole tip. Things happen quickly, but it makes the best milk. I was sad when my pal asked for that back. Ive been meaning to order one for a while now.

So, try swirling the shot the in the cup before you pour. stretch as gently as you can, and then open the steam full blast to texture to 155F. Thats what I do.

Here's a photo of what I'm talking about. Right photos is after 30 seconds (bubbles just starting), left photo is after 3 minutes (yuk).

I'll try all the swirling suggestions and see what happens.

Oh...and by the way. I have a one hole tip as well. Same problem.

The only thing I can guess, is, maybe you are stretching too vigorously, but incorporating for long enough to make it pourable for latte art, then, as the drink sits, the bubbles that were "hidden" emerge and annoy the be-jebus outta ya. I get bubbles like that If i messed up the stretch but "fix" it with the the texturing.

Try this.

For the stretching phase, dont open the steam all the way, I open mine about 1/2, and be as gentle as you can, VVVERRRRRYYYYYYY softly incorporating air.. Take it too 100F. Then, dip the wand and open the steam full blast to 160F. Dont tap the pitcher too much.. I only tap once, and then gently swirl it it for about 30-45 seconds.

I keep my pitchers in the freezer at all times. When Im going to make a milk drink, the VERY 1st thing I do, is fill my pitcher with milk, and put it back in the freezer. Then, I build my entire shot and pull it. THEN I go get the milk and stretch it. I know both of our machines have plenty of steam power, but If I dont do that, and just fill a frozen pitcher with milk and start stretching, I get poor results. It might be a crutch, but Idc.

If you continue to have problems, maybe try out the "new" 4-hole tip Chris has, with the smaller .9mm holes. The general consensus is that once you get a handle on the 4-hole tip, they make the best milk.

I get my best milk when Im making enough for at least a double capp, 8oz. If Im only stretching enough for a 4.75oz capp, Ive got to try incredibly hard to get good results..and it often doesnt happen. For me, with the single hole tip, the more milk, the better the results. If Im making enough milk for two lattes, it does take longer, but the milk is great. Maybe thats the secret with the single hole tip, because even though it takes a little while, the milk textures for sooo long. HMMM.

Keep us updated.

use an instant chocolate powder or something like that which is suitable for making hot chocolate. steam your milk and pour over it not on espresso. if you still get same bubbling soda effect with hot chocolate too then change your milk and try till you find the right one. It's not only the fat, you need milk with higher protein percentage. Milk is a seasonal product, to avoid changes in taste and texture, most companies try to stabilize it, otherwise you'd get different taste/texture from the same brand every now and then.

buy different brands and after every time you steam, raise the pitcher to your ear and listen for bubbles' exploding sound. If the sound is clearly heard and persistent then you should definitely change your milk.

JmanEspresso wrote:For the stretching phase, dont open the steam all the way, I open mine about 1/2, and be as gentle as you can, VVVERRRRRYYYYYYY softly incorporating air.

This may be the problem. I have a Mini Vivaldi which uses a "on/off" style steam arm from the pro S5 machine. I can only open it fully. So how do they do it on the pro machines?

Fully open is VERY powerful and works great for rolling, but I think the mega-velocity sucks in too much air during the stretching phase (no matter how careful you are).

I also have no ability to turn down the steam pressure since it is controlled using a non-adjustable thermastat.

I've tried all tips (1,2,3 and 4 holes). They all give the same effect.

My best results have happened if I trick the machine by running it in 15A mode. This way the brew boiler gets priority and if I time it right by starting to steaming when the brew boiler is heating, the pressure will drop below 1 bar during the stretching phase and the heater comes on during the rolling stage. Call this "pressure surfing" if you like.

As a permanent solution, I'm thinking of one of these options:

1. Add a stopper to the steam arm to limit the throw.
2. Add a PID to my steam boiler so I can adjust temperature (and therefore pressure).

Or how about adding a resistor to the thermostat on the steam boiler to "trim" it down to a lower temperature/pressure. Would this work?

What do you think?

malachi wrote:Don't over-stretch the milk; swirl milk aggressively in pitcher (after steaming and letting sit for a minute while pulling the shot).

In other words...

1 - You're overstretching the milk. You need to go from stretching to steaming at a lower temp.
2 - You can address some of the bubble issues by steaming before you pull the shot, letting the milk settle, and then aggressively swirling the milk in the pitcher while the shot pulls. In addition - if you do this you'll get a better idea of how good your milk technique is (if the milk separates while you're pulling the shot - you've got issues --- for example).


It's also possible that:

1 - During stretching you've got the tip breaking the surface periodically (will create more bubbles).
2 - You're over-steaming the milk as well (will cause the milk to separate into foam and milk and if poured right after steaming could create the impact you see).


In other words...

1 - I don't think it's the tip or the machine.
2 - I think it's the technique.

I pretty much certain I'm not overstretching or oversteaming. These were my first thoughts as well so I did a LOT of experimenting to rule these out.

I'm pretty sure at this point it's related to excessive steam jet velocity and flow rate during the stretching phase. I have some more experimenting to do to be sure, but this is the current direction I'm heading.

Next step will be to figure out how to lower it during the stretch phase but then get it back for rolling.

Interesting about the steam on the mini.. Did you upgrade something? I was under the impression even with the steam lever, you could open it half way.

Id say that has got a lot to do with it.. Unless Im stretching A LOT of milk at one time.. I dont open it all the way until I texture/roll the milk.

No mods. It's spring loaded. Open or closed.

It would be nice if it could be "ratcheted" half way, but that's not the way it's designed. It's really taken directly form the big S5 mulit-group.

I imagine a barista in a busy cafe using a S5 would normally be moving fast and steaming larger volumes of milk, so maybe that's the reasoning behind the on/off style lever.

I'll look at adding a stopper to the top end, but it is VERY sensitive, so there really is no 50% position.

have you washed your pitcher with soap lately and scrubbed it with a brillo pad?

or do you just rinse it out?

jon

I just rinse. But I have 3 pitchers and they give a similar effect. Are you thinking there is something on the inside that could cause it?

To be honest I never thought of this. I'll give it a good brilo scrubbing to be sure.

i think its a small amount of something in the inside of the pitcher creating an unstable foam. similar to whipping egg whites in a bowl that isnt clean or has a small amount of the yolk in the egg whites..the foam collapses.

it could also be the crema of the espresso collapsing.

but it cant hurt to use soap once in a while.

jon