Ok, here's the issue:  we just swapped milk suppliers and are now using the first and only organic milk producer in the state.  We were previously using Naturally Preferred organic milk from Kroger.

Anyway, we've run into a strange issue with the new milk—it doesn't seem to take the heat of steaming very well.  At 130-140°, it's noticeably scalded and seems to taste best around 100°F.  Even at that temp, it doesn't stretch nearly as well as the old milk.

Has anyone else had this issue or know what would cause it?  

Views: 3497

Reply to This

Replies to This Discussion

That's an interesting finding...

Is it the same with whole and skim?

You'd think since milk is pasteurized at 166-170˚F range for 20-25 seconds, the temperature your steaming it would not alter the flavor.

Have you tried other brands just for comparison?
As of now, we're only getting whole milk from the new producer (it's the only thing their farm produces). I do know they use a low-temperature pasteurization method, but i'm not sure exactly what temp they use.

Perhaps it has to do with the non-homogenized nature of the milk?

In iced drinks, it tastes fantastic. If only we can figure out how to steam it correctly, we may stick with it.
I would assume it is the non-homogenized issue that is your problem. I worked the coffee bar at an organic restaurant once and they purchased organic non-homogenized milk. I had lots of trouble steaming it to proper texture and temperature, but did notice that shaking it vigorously (and I really mean a lot here) before heating, would help it to steam a bit better.

Hope this helps.

Adam Wilson said:
As of now, we're only getting whole milk from the new producer (it's the only thing their farm produces). I do know they use a low-temperature pasteurization method, but i'm not sure exactly what temp they use.
Perhaps it has to do with the non-homogenized nature of the milk?
In iced drinks, it tastes fantastic. If only we can figure out how to steam it correctly, we may stick with it.
It's non-homogenized? That's your problem. Homogenization breaks the fat up considerably. The fat and proteins create the foam. Without the fat as a buffer, there's no doubt that the steam will scald the milk it comes into direct contact with, even if the average temperature hasn't reached 140F yet.

I'm no chemistry expert, but based on my experience, this is the logic that I came up with.
Great topic!
Does it taste better than your previous milk? Just wondering...
My idiot self didn't think about the fact that this doesn't happen with skim milk. What are the cows eating? How does pasteurization affect the milk's chemistry?

Jason Haeger said:
It's non-homogenized? That's your problem. Homogenization breaks the fat up considerably. The fat and proteins create the foam. Without the fat as a buffer, there's no doubt that the steam will scald the milk it comes into direct contact with, even if the average temperature hasn't reached 140F yet.

I'm no chemistry expert, but based on my experience, this is the logic that I came up with.
If we're talking about a cold glass of old milk vs cold glass of new milk, the new stuff tastes much better: richer, creamier, and sweeter.

Matthew Gasaway said:
Does it taste better than your previous milk? Just wondering...

Facts that I've found researching online today:
1. Low-Temperature Pasteurization (used on our new milk) involves heating milk to 145°F for 30 minutes
2. High-Temperature-Short-Time Pasteurization (the common method) heats the milk to ~160°F for 20 seconds.
3. Ultra-High-Temperature Pasteurization (which is what Naturally Preferred and Horizon organic brands use, as well as most "extended shelf life" brands) heats the milk to ~270°F for 1-2 seconds.

Homogenization seems a likely culprit, but if it's the fat/cream that's keeping the milk from scalding, why doesn't my skim milk taste burnt at 140°? (Skim milk is not homogenized, as the milk is allowed to separate and the cream "skimmed" off the top to produce fat-free milk).

I can't help but think it has more to do with the pasteurization, as the milk is processed at nearly the same temperature to which most baristas steam it. HTST and UHT methods, on the other hand, process milk at temperatures higher (or MUCH higher in the case of UHT) than we care to see in a cappuccino.

Thoughts?
Adam Wilson said:
(Skim milk is not homogenized, as the milk is allowed to separate and the cream "skimmed" off the top to produce fat-free milk).

I can't help but think it has more to do with the pasteurization, as the milk is processed at nearly the same temperature to which most baristas steam it. HTST and UHT methods, on the other hand, process milk at temperatures higher (or MUCH higher in the case of UHT) than we care to see in a cappuccino.

Thoughts?

Are you sure skim is not homogenized? Even though it's labeled fat-free, I'm pretty sure there is still a trace amount of fat left in it, which would slowly come to the top if not homogenized. I really think your problem lies in the non-homogenized area. I hated steaming that stuff, but, as I said, shaking the hell out of it right before steaming did make it tolerable.
Milk sugar is a complex sugar molecule that breaks down when heated into simple sugars. The simple sugars are sweeter on the tongue than the complex sugar, and this is why milk heated to the correct temperature range will have enhanced sweetness. More heat will break down the simple sugars into molecules that are no longer sugar. This is a physical property of the molecules in relation to specific temperatures and time, and is not dependent on fat or homogenization. Quick homogenization does not allow enough time for them to break, even though the temperature might be higher than that to which you would steam milk for drinks.

The Betalactoglobulin protein will unravel its coiled structure with heat, and the flavor will change according to how much it becomes denatured in this way. Scalded flavor is a combination of broken down simple sugars and denatured proteins.

When I have used non-homogenized milk, I found the flavor to be quite off from what we normally get in homogenized milk. I do not know what exactly it is about it that makes it taste different, we may simply not be accustomed to it, and therefore write it off as "bad" flavor. This is, of course, the flavor that humans have known from milk for thousands of years, we are the ones drinking different tasting milk now-a-days. The fact is, homogenized milk is cooked milk and takes on different flavors than raw milk.

You can ponder this endlessly, you can taste test, you can shake and rattle your milk till the cows come home. Or you can switch back to organic homogenized milk for the flavor to which you are accustomed. Serving raw milk is as significantly different from it's cooked counterpart as serving sushi is from seared steak. Well, that's a bit of an exaggeration, but the point is that you will not get it to taste the same.
I would like to echo what Kevin Ayers wrote about shaking your milk before steaming.
Also, did your previous milk have vitamin D added? It's something i would never have thought of, had i not run across this problem in a training last week. We were testing milks from the double homogenized,ultra-pasteurized darigold, to the pacific northwest standard, sunshine dairy, local favorites, golden glen which is low-temp pasteurized and a raw milk. the flavor of the raw milk was the best; nutty, buttery, complementary to the central American SO espresso that we were testing the milk with, however it was very difficult to work with as far as getting a nice micro-foam throughout. we experienced similar issues with the low-temp pasteurized milk. Both the double homogenized, ultra-pasteurized milk and the fortified homogenized,pasteurized milk steamed up fantastic and tasted "normal". These two milks were also the only two on the table that had vitamin D added.
Is blending your milk an option? 60% new stuff 40% kroger brand? During our experiment, we had fantastic results using this proportion. We had the rich nutty flavor of the raw but the texture of the homogenized milk.
Also, what the cows are eating can effect the quality of the milk. grass-fed vs. grain-fed milk can taste vastly different and have different mouth feel when cold or steamed.

Reply to Discussion

RSS

Barista Exchange Partners

Barista Exchange Friends

Keep Barista Exchange Free

Are you enjoying Barista Exchange? Is it helping you promote your business and helping you network in this great industry? Donate today to keep it free to all members. Supporters can join the "Supporters Group" with a donation. Thanks!

Clicky Web Analytics

© 2020   Created by Matt Milletto.   Powered by

Badges  |  Report an Issue  |  Terms of Service