Ask Surly Amy: Homogenization, How Does That Work?

Ask Surly Amy

Dear Surly Amy,

I was peacefully buying groceries the other day when a man came up to me, stared into my cart, and then informed me that I shouldn’t be buying 2% milk because it was homogenized and that would burst my blood vessels.  This man knew this because he had had a history of strokes, which he began narrating to me in tedious detail.  As a skeptic dedicated to being able to counter ridiculous pseudo-scientific claims, my instinct, which I acted upon, was to flee to the aisle of feminine hygiene and count on his patriarchally instilled fear of anything menstrually related to keep him from following.  Was there a better way to handle this?

~fucking homogenization, how does that work?


If homogenized milk was bursting blood vessels we would pretty much ALL BE DEAD by now. Think for a moment when this milk fear started. Within the last few years, correct? So why aren’t all the people in America dead? Think about the 1950’s, people! All that milk and bacon for breakfast should have wiped America clean off the freakin’ map!

And why pick on 2%? The full fat version is usually homogenized too.

Are you drinking 2% because you think you’re fat? Cuz your not. You could be drinking whole milk if you wanted to. (Thank you, Napoleon Dynamite.)

I think you handled the situation perfectly. In fact, the only thing that would have made it funnier is if you had opened a jar of chocolate milk, popped in a straw and and had started sipping it while slipping off to the tampon isle. Spontaneously combusting would have been funny too but that is a little difficult to pull off in the grocery store. Or ever.

The homogenization process is used to help keep milk mixed. Milk that is not homogenized will separate (like oil and water based substances do) and there will be a thick, creamy layer on top and a watery layer on the bottom. In earlier times, the thick, creamy top layer was used to judge the quality of the milk. The more fat the better in ye old days because sneaky milk producers were known to “skim off the top” and use the stolen fat to make butter and ice cream. Thus rendering American housewives completely useless! One could argue that homogenization has helped to mix things up with feminist movement. Suddenly ladies across the land realized that there was more to do than hoard fat and churn butter!

Back to homogenization: During or directly after the pasteurization process, milk is run through tiny tubes or nozzles at high pressure where the fat molecules in the milk are either broken down, reduced in size or stripped thus preventing the milk from separating into water and cream. That’s pretty much it.

Kind of ironic. I mean the guy thinks homogenized milk will burst your blood vessels when in actuality homogenized milk is just slimmed down and mixed-up regular milk. I would think the big intact un-homoginzed fat molecules would pack a bigger punch and be more likely to clog up the old arteries. But the fear-based, milk-scare is based on the idea that the tiny broken down fat molecules in homogenized milk are somehow different from other fat molecules and are rapidly seeping into your blood stream and destroying your arteries. I couldn’t find any legitimate studies to back this up.

A drawback to homogenized milk is that when the fat globules are broken down it can cause the milk to spoil quicker. There’s that. That is one of the reasons pasteurization and refrigeration are necessary. And the high pressure and heat of the homogenization process acts as a second pasteurization in most cases. Some people who are used to raw milk also notice a change in flavor after homogenization and homogenized milk is slightly more difficult to digest than raw milk. This is because some of the natural enzymes are stripped. It is usually whiter in color as well. But this will not give you a stroke or cause you to explode.

From what I could find on this topic, this seems to be just another version of the natural fallacy. There is a group of people who are afraid of any type of processing. This mindset has been perpetuated by alternative medicine and supplement pushers and not based on scientific evidence. It’s based on trying to sell you ‘natural’ alternative products.

Too much fat is bad for anyone. But mixed up milk won’t kill you. Watch your diet, get some exercise and enjoy a milkshake now and then.

The truth THEY don’t want you to know about homogenized milk is that, well, it’s mixed.

Got a question you would like some Surly-Skepchick advice on? Send it in! We won’t publish your real name, unless you want us to and creative pseudonyms get bonus points! Just use the contact link on the top left of the page.

*Ask Surly Amy is meant for entertainment purposes only. All advice should be taken with as much skepticism as anything else, really.

Amy Roth

Amy Davis Roth (aka Surly Amy) is a multimedia, science-loving artist who resides in Los Angeles, California. She makes Surly-Ramics and is currently in love with pottery. Daily maker of art and leader of Mad Art Lab. Support her on Patreon. Tip Jar is here.

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  1. I would like to find non-homogenized milk for cheese making. Going all Jet Li on the fat globules interferes with proper curd formation. Unfortunately these days homogenization goes hand-in-hand with pasteurization and pasteurization with rare exceptions is mandated by law. Apparently there exists whole milk sold in “cream top” form, but I haven’t been able to find any within non-driving distance.

  2. We have a local dairy that sells non-homogenized milk, and I LOVE IT.

    It is wonderful, although the first time a giant blop of cream lands in your coffee, it’s a little disconcerting.

    It absolutely lasts twice as long as regular milk in terms of going bad. And it is still pasteurized, which is very important.

  3. When milk is “raw,” does that mean it’s unhomogenized or that it’s unpasteurized? Isn’t there some movement out there that’s against pasteurization too, or am I just getting the two terms confused?

  4. You could have told him that homogenization indicates that it was homeopathic milk that had the shit succussed out of is and that therefore the fat molecules prevented heart attacks.
    Or maybe that it was “moon juice” that the astronauts learned how to make while they were sequestered during the filming of the hoaxed moon landing that was released to test the gullibility of the American public. (At which point you could point out that gullible does not appear in the Oxford English dictionary and that he should look it up.)
    Or that you had to go, because you were getting a tingling sensation in your anus and that means that Deepak Chopra was calling you on the big white telephone to inform you that your chakras are ready to pick up and that it will be $17.50 (tips are appreciated) and that he couldn’t get the regret out of your Yoni so there was no charge for that.

    Then, as you walked away, tell him you are sorry but your sarcasm switch is acting up due to unusually high levels of complete horseshit that you have had to sift through lately.

    I don’t think he’d get it though.

    Sorry, my snark button is stuck. Happens every time I go near the Free Republic site. That place is a cesspool, dirty’s up the hardware..

  5. That is interesting. I wonder if the same kind of mixing (on a larger particle size) is going on when the milk is expressed from the cow.

    The “natural fallacy” is certainly involved but I have to think the anti-big agriculture bias must be a part of the problem. I wonder if homogenization would bother these people if it was something done on small dairy farms.

  6. “I would think the big intact un-homoginzed fat molecules would pack a bigger punch and be more likely to clog up the old arteries.”

    This doesn’t seem at all obvious to me. I don’t know much about the actual mechanisms of artery clogging, but if it’s really just a matter of fat globules sticking to the blood vessel walls, I could imagine, for example, the higher surface area to volume ratio of the smaller fat globules making it easier for them to adsorb. has what looks like a reasonable rundown of the theory behind homogenized milk increasing the risk of heart disease, and some of the problems with said theory. Clearly the website hosting it has an agenda, so salt to taste, as usual. Given the number of references on the wikipedia article about homogenization that refer to Bovine Xanthine Oxidase and atherosclerosis, it seems likely that something along the lines of the argument presented at the link above is what the gentleman at the grocery store had heard about.

  7. I would think the big intact un-homoginzed fat molecules would pack a bigger punch and be more likely to clog up the old arteries.

    I think it’s the other way around. Big globs of fat have a lower surface area to volume ratio so less gets absorbed. They also have more surface tension and stuff. The smallest fats can just squeeze right in.

    Does anyone have any real information on this they’d like to share?

  8. Milk doesn’t last long enough in my house for it to matter. We’re from Wisconsin. We bleed cream and are made out of hard, sharp cheddar.

    We drink skim because at the rate we drink milk, we really would be dead if we kept drinking whole milk.

    Raw milk is unpasteurized and is potentially dangerous, as it can carry nasties like TB.

  9. where the fat molecules in the milk are either broken down, reduced in size or stripped

    Homogenization doesn’t actually change the milk fat molecules, it just creates such small globules of fat and protein they stay in suspension rather than coalesce and raise to the top.

    I wouldn’t be surprised if that made them more accessible to our digestive processes, but thinking you could absorb even super-tiny lumps of fat through your intestines requires a high level of ignorance about how we digest and absorb fat.

  10. @hamertime: When milk is “raw,” does that mean it’s unhomogenized or that it’s unpasteurized?

    Raw milk is straight from the cow, goat, sheep, or whatever. It is not homogenized or pasteurized. About thirty people in my town just came down with a nasty case of E. coli after drinking some.

    I wouldn’t mind getting my hands on raw milk because it too is supposed to make better cheese. My reading so far suggests that the low pH over a long aging process is supposed to destroy any baddies that might be in there, but I’d do a lot more reading before experimenting on myself. This is moot, however, because I can’t buy any legally.

  11. I used to get raw milk from a farm in Michigan. We did it so I could have milk, even being lactose-intolerant. Something about there being some natural lactase present in the milk before pasteurization.

    I never looked into it scientifically, but my body that can’t handle Goldfish crackers or M&Ms without medication digested it fine.

    And yes, definitely creamy layer up top – but they sold it in both regular (thick layer) and skim (thin layer), so that was nice.

    Now I just get lactose-free pasteurized milk, but it is good to know for the dairy challenged.

  12. @davew:
    I’m not super lactose intolerant, I’m not going to die from milk, but it’s quite an uncomfortable experience. That said, I can eat yogurt just fine without feeling sick.

    I have no clue how common experience among the lactose intolerant is, though.

  13. Sorry as Amy says the tase of homoginised milk is different and I cannot stand it. I think it is the high temperature that is used it tastes like boiled milk and I can’t stand that either.
    By the way all the literature says that cheese aged two months loses all the nasties and I haven’t had any problems with my cheese yet. I am buying milk and I donot know if it pasturised or no and the man who sells it to mew speska no english so I can’t find out so I leave it two months to mature to be on the safe side.
    You used to be able to buy raw milk in th UK from herds that were TT tested. I even worked in a farm dairy during my youth and bottled milk by hand. The local top restaurants used to buy our milk as it was from pedigree jersey cows and the cream content was very high.
    I think homoginisation is another think to help the seller not the buyer like lots of things we are forced to buy these days.

  14. @scrapps:

    I don’t think anyone will die from lactose intolerance. It just gives you sever intestinal distress.

    With me it varies I can go for years with little problems then all of a sudden my sensitivity to dairy will increase.

    Also certain foods affect me more then others. Strange things like I can eat an entire pizza covered in mozzarella and be fine, but if I eat one fried mozzarella stick I”ll be doubled over for the next 12 hours. I suspect they add something to the ones they package for deep frying.

  15. @ Eric

    “A hypothesis has repeatedly been promoted that xanthine oxidase from homogenized bovine milk is absorbed intact, damaging cardiovascular tissue by depleting plasmalogens and initiating atherosclerotic changes that culminate in heart disease. In the light of recent experimental evidence, the present paper examines the validity of this hypothesis and associated claims. The evidence leads to the conclusion that 1) absorption of dietary xanthine oxidase has not been demonstrated; 2) a relationship between intakes of homogenized milk and levels of serum xanthine oxidase activity have not been established; 3) a direct role for xanthine oxidase in plasmalogen depletion has not been established; 4) neither liposome formation during homogenization of milk nor absorption of intact liposomes from the gastrointestinal tract has been demonstrated; and 5) data are lacking to support the claim that large doses of folic acid inhibit xanthine oxidase in vivo and/or are therapeutic in heart disease. Experimental evidence has failed to substantiate, and in many cases has refuted, the xanthine oxidase/plasmalogen depletion hypothesis.”

  16. @Dionigi:
    I’ve had raw (chilled) milk, and didn’t find the basic taste to be different. The fat content felt different of course, but I can drink anything from 1.5% to whole milk and enjoy it. (Even tried corn flakes with cream once when there was no milk, but that was a bit too rich.)

    I have however also had ultra-pasteurised milk, the kind that has a shelf life of months and isn’t kept chilled. That does have a nasty boiled milk taste.

  17. I tried for the longest time to find an answer to this: Is drinking raw milk in the U.S. any more dangerous than eating raw fish? They both have somewhat serious potential health risks and occasionally do make people sick. I never was able to find an answer. I just wonder if we overlook it with sushi because it’s trendy, or keep stigmatizing raw milk out of habit. Anyone have any facts to share?

  18. I think there’s a risk with any raw foods you eat or drink. And just consider the various items that are used untreated: milk, eggs, fish, beef and of course a variety of fruits and vegetables (that carry a lot less health risks than raw animal products). So why will people consume them uncooked anyway? Usually because they do have a different taste. Or because the heating process will render them unusable for your production process (like mayonnaise, cheese, etc…).

    It’s a risk you have to take if you want to enjoy the taste of these products. But on the digestive level I don’t think it’s really any more or less healthy than food that’s been heat-treated. The digestive system will just need to work a bit harder to process it.

  19. There is a risk, but it is a different risk. Different bacteria (and potential parasites!) are found in fish and cows.

    With Sushi, you have the risk of becoming an intermediate state in a worm’s lifecycle–which is very bad.
    With milk, the danger is primarily bacterial, which is why pasteurization is important.

    It looks like people are still confusing raw milk, whole milk, pasteurized milk, and homogenized milk.

    I’ll have to write faster on a post explaining all that ;p

  20. Oh, I wasn’t suggesting that homogenisation is the same as pasteurisation. I was merely responding to the raw vs. processed foods issue that came up.

    Unless you weren’t replying to me specifically of course.

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