laythss Senior Member Joined: 19 Feb 2005 Posts: 48 Location: California Expertise: I live coffee
Espresso: La Cimbali M23 Grinder: La Cimbali junior
Posted Tue Oct 15, 2013, 8:20am Subject: foam starts popping.
a picture is worth a thousand words they say... so this is what happens 30 seconds after pouring, starting and mainly at the part where there it is darker i.e more coffee i guess:
www.whitefoam.me/images/latte_art.jpg The setup: Coffee: Freshly roasted Yemani Sanani beans... I am no expert in roasting (1 week into the hobby) the roast is stopped 10 seconds after first crack. dark brown but uneven. Roast is 30 hours old, It was left to breath for first 24hours. (giving details just because this might have something to do with fresh roasted beans possibly).
Milk: Full fat. I am no expert in micro foam either, but as i learned by practice for the last two years and by an acquaintance in intelegensia, this is micro foam. I can do a rosetta as well as a heart 8/10 times, this pic is not one of them.
Espresso: a restretto shot (18g coffee) 1-1.5 oz in 26- 28 seconds. exen pattern middle through naked portafilter.
Equipment: Roaster: WhirleyPop Espresso and MILK : La Cimbali M27 Grinder Mazzer Mini.
What is causing this? is this typical ? am I doing something wrong with the frothing? any ideas of how to troubleshoot this? I appreciate any help.
Posted Sun Dec 1, 2013, 7:53am Subject: Re: foam starts popping.
I cannot tell what you're asking. That may be why no one has attempted to answer. Stable microfoam takes a few minutes to break. ARe you saying your micro foam breaks down too quickly? Is that what you mean by popping? Foam breaks down from smaller into larger bubbles because of many factors that include heat, protein quality, water vapor, contaminants in the cup including chemicals and particles in the coffee and relative humidity.
You could begin this diagnosis by objectively evaluating your foam and techniques. Try texturing your milk and pouring it into a preheated clear glass container that resembles your latte mug. Add one drop of green or blue food coloring to the glass BEFORE you pour. This doesn't hurt the foam--much--and it will give you an unmistakable look at the separation between liquid milk and your foam, what I call the interface. As the milk sits, the liquid portion will grow in volume, the interface will rise, the microfoam will break into larger bubbles. Measuring the milk temperature, varying the fat content, and observing the amount of time the foam remains palatable will help you identify the variables you can control.
I play go. I use Macintosh,. Of course I ride a recumbent.
I can't see your picture but there are 2 probable causes for your milk/latte art breaking down quickly.
Your espresso is too fresh. Espresso less than 3-4 days off roast has an insane amount of CO2 within the coffee. You probably notice that your shots have lots of crema? If so, that crema will break down your milk really fast after pouring.
Your espresso machine isn't keeping the pressure high enough through your entire steaming process. If you aren't getting a solid 1-1.3 bars of pressure while steaming milk, you will likely get lots of little bubbles in your milk that won't go away
Another less likely issue is your steam is too wet. This can be caused by the boiler in your espresso machine overfilling some, which allows more water into your steam than you need. It may also be a good idea to clean your steam tip holes on your espresso machine, sometimes a little clog can cause issues with your milk too.
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