A while back, we noticed that Mia didn’t want to drink bottles of breastmilk that I had painstakingly prepared. At first, we thought it was because she didn’t like drinking from bottles. We changed the bottle teat. We tried when she was less tired. Sometimes she would drink it, sometimes she wouldn’t.
Finally we tasted the milk ourselves. Freshly expressed breastmilk was mild and sweet. The milk that we had thawed from the freezer was horrible.
I felt awful. We had been trying to force horrible tasting milk into Mia’s mouth!
So, we ditched the ‘liquid gold’. I had no qualms about it. It’s hard work to build up a stash of breastmilk but there was no way I was going to feed it to Mia.
Why did this happen? Somewhere between expressing, freezing, storing and thawing, the taste of the milk changes.
I read around the topic on the internet. Some women’s breastmilk has too much lipase (an enzyme), which means that breastmilk starts changing in flavour within a few hours of storage. This is not what happens to my milk. Mia is happy to drink milk that has been refrigerated for a few days.
Another theory that sounded promising is to do with the way frozen breastmilk is stored in the freezer. The freezer has a defrost cycle, so if milk is stored on the ‘floor’ of the freezer, it might defrost and refreeze a little each time the freezer does a cycle.
To test this, we made three samples of milk. One was refrigerated. Another was stored on the floor of the freezer. The other was stored on the freezer shelf. After three days of storage, I also expressed a fresh milk sample to add to the experiment.
It was a single-blind taste test. I knew which sample was which and Damjan did not. Here are his notes.
It turned out that thawed breastmilk tastes like coconut! Also, all samples were drinkable and close to indistinguishable.
Our next theory was that it was the age of the breastmilk that mattered, rather than the storage method. So for two weeks, every second or third night, I made a breastmilk sample and froze it.
Last week, we got to do another blind taste test.
Alas (or hooray?), all samples were equally drinkable. The age of the milks did not seem to relate to how strong the flavour was. Damjan wasn’t able to rank them by age.
So we haven’t really gotten to the bottom of it.
At least we know that we can freeze milk for at least two weeks. In fact, on Monday, we sent Mia to childcare with a bottle of thawed 16-day old milk and she drank all of it.