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Why do I need to boil 1L of water?

(20 Posts)
FreNika Sun 25-Sep-16 20:25:53

I'm wanting to copy the Tommee Tippee Perfect Prep machine and boil some water to initially kill the bacteria in the formula and then top it up with filtered water. It means that I don't have to boil 1L of water every time. However I don't want to do it if boiling less than 1L of water water is more dangerous for my babies. I can't find the reason behind 1L anywhere. Does anyone have a clue or can point me in the direction of where I can find the answer?

Ginmakesitallok Sun 25-Sep-16 20:29:48



500ml of boiled water is as sterile as 1 litre

ComeLuckyApril Sun 25-Sep-16 20:30:25

Yes it's because they go on to say to use within half an hour - they know that quantity of water would still be more than 70 degrees. I do similar. We boil fresh water each time and use straight away.

ComeLuckyApril Sun 25-Sep-16 20:31:05

I meant to say, we only boil what we need.

5madthings Sun 25-Sep-16 20:33:54

I don't know re quantities other than the heat thing ie how long it takes to cool to below 70 but I do remember something about not re boiling water so fresh water each time not just topped up.

dementedpixie Sun 25-Sep-16 20:35:02

If you boil less than 1 litre then it will cool down faster than 30 minutes so you need to use it sooner to be sure it is still more then 70 degrees

FreNika Mon 26-Sep-16 02:51:08

Thanks ComeLuckyApril and Demented Pixie. I've just started using formula and am getting conflicting and confusing advice bit it seems less than 1L is ok.

I thought there was something about 1L being safer because the minerals are more concentrated in smaller quantities of water when boiled or something like that.

My babies were born premature and under birth weight, hence the need to be super safe.

FreNika Wed 28-Sep-16 05:23:44

Ginmakesitallok, go drink your gin. Obviously you have no idea what I'm talking about and have missed the point entirely. Perhaps you should double check what you read before replying so rudely.

Ginmakesitallok Wed 28-Sep-16 07:03:54

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CheshireSplat Wed 28-Sep-16 07:11:40

Gin that's totally uncalled for
This is Infant Feeding not AIBU. And your first reply didn't exactly relate to the OP's question as she didn't mention anything about sterility. Why on earth did you have to be so rude?

OP looks like you've got your answer.

CheshireSplat Wed 28-Sep-16 07:15:45

Oh, OP, I've just remembered. The Perfect Prep machine heats the water to 70 not 100 as there's a theory 100 will kill of the good stuff in the formula.

So looks like you're best off boiling a little of water and waiting 30 mins, so it'll be 70 degrees, which I guess is why the PP was invented. Would it work to get a thermometer and mix just boiled water with cold and checking it's 70?

itlypocerka Wed 28-Sep-16 07:16:23

If you live in a hard water area and don't have a kettle of the type that has a little sieve at the spout, then you do have to consider minerals a bit.

- empty your kettle completely before refilling it with fresh water, so you aren't boiling and reboiling water that's been in there a while (that can increase the minerals)

- boil at least 3 times as much water as you need for the formula, so if you need 100ml then boil 300ml - because whatever little bits of precipitated minerals will mostly sink towards the bottom and won't come out in the first third of what you pour.

Like pp have said, you'll need to work out for yourself what length of time after boiling you can still be confident the water will always be still above 70C (it will be a shorter time on colder days)

CatsCantFlyFast Wed 28-Sep-16 07:18:44

There is research that suggests the 70 degrees that the perfect prep machine uses, along with the small amount of heated water, is not enough to kill the bacteria potentially in the formula powder. Personally I wouldn't want to be relocating a method that raises questions about its effectiveness

CatsCantFlyFast Wed 28-Sep-16 07:19:33

Like this

CatsCantFlyFast Wed 28-Sep-16 07:19:52


FreNika Wed 28-Sep-16 09:21:40

Thanks guys, exactly what I was looking for. I am in a hard water area so there are always a lot of minerals at the bottom of the kettle only after a couple of days so I was worried the smaller amount of water would have more minerals because of the evaporation process. itlypocerka, I'll take your advice.
NotWithoutMyMerkin - I had seen that report before, it's convinced me not to buy the machine. However, I thought the concept was a good one. I'm going to be using the thermos method which it outlines in the report so that I can save energy and time on boiling water.

FreNika Wed 28-Sep-16 09:23:38

Oh, and thanks CheshireSplat, I've ordered a thermometer just to double check the water in the thermos when I pour it.

Ginmakesitallok Tue 17-Jan-17 17:50:54

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FreNika Tue 17-Jan-17 18:18:33

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Ginmakesitallok Tue 17-Jan-17 18:24:43

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