How to fill a hot water bottle

Last time, I introduced a knitting pattern, the Joules & Joulietta Hot Water Bottle Cover, to make a cover for your favourite hot water bottle. It's just so much better when your hot water bottle has a knitted cover on, then you can have a super-cozy bottle that's not just warm but is also great to hold too!

But do you know you to fill a hot water bottle? It's surprising that many people don't actually know how to do this. ​So here's the method my mother taught me, and mother's are always right eh?... (Well, that and the manufacturer's instructions of course!)

Firstly it is important that the bottle is emptied in the morning after it is finished, so we are starting now with a hot water bottle which is out of its cover and empty.

So here's what to do:

#1 ‐ Fill a kettle with freshly‐drawn cold water. Do not use hot water, as the hot water pipe often contains minerals that degrade the rubber of the bottle. If you don't have a kettle, then you can heat the water in a saucepan with a pouring lip, or in a microwave.

Heat the water until it is hand‐hot (about 42ºC/108ºF). You do not need it to boil, and in fact if it does you then have to wait a long time for it to cool to an acceptable heat. Bottles can leak from time to time, so it is important that the water will never scald you if the rubber gives way.

Many modern kettles have variable temperatures which allow you to set a lower shut‐off point. If you have an older‐style kettle, then wait until the water is just starting to sound "noisy" and then immediately turn it off.

Pour the water into a jug that pours well and add cold water until the temperature is right. You should be able to briefly put your hand into it without scalding.
​
#2 ‐ Now hold the hot water bottle upright over a sink. Grasp it firmly by the top and carefully pour the water in until it is about 2/3rds full.

#3 ‐ Hold the bottle at a slight angle and then gently lower it onto a flat surface until you see the water at the top. This expels all the air. Insert the stopper and close it firmly but without too much force. Press the bottle gently, then turn it upside down to check for leaks.

Dry the opening around the stopper and any damp patches on the outside. Feel the bottle to make sure that it is not too hot. It should be comfortably warm, not too hot to hold at this point. If it feels a little too hot for comfort, then pour a little of the hot water out and run in some cold.

#4 ‐ Place it into its cover and prepare additional bottles if more are required. Ideally, place two in each bed, one at the top with your PJ's wrapped around, and one for your feet. If you do this about 20‐30 mins before you go to bed you'll be super comfortable when you snuggle under the duvet.

Just to note, though:

• It is fine to gently hug your bottle while you are still awake, but don't press it too firmly or it could burst.
• However, for a child's bed, it is best to remove the bottle before they get in.

#5 ‐ In the morning, take the bottles out of their covers and drain them completely. Hang them upside down to store and to drain further. It is a good idea for each stopper to be attached to its own bottle by a string around the neck, as different bottles can have slightly different threads and you want your stopper to be completely water-tight.

#6 - During the summer months: When the bottles are not in use, store them upside down in a dark, airy place. Always buy a good rubber bottle rather than the cheaper imitations and replace them every year or two. It's also a good idea to check the bottle really well before using them for the first time each season. Filling them with cold water and gently squeezing gently will soon show if any areas are compromised.

And a quick note on hot water bottles… These come in all sorts of sizes and designs. You can use the Joules & Joulietta Hot Water Bottle Cover pattern for both regular size bottles and also for travelling size bottles and microwave packs. I am not so keen on the microwave versions as they can get hot spots, but they do suit some people. However, an important note:

• Don't place hot wheat packs into your bed as they can go on fire!! These are great for sore necks and backs, but are not a substitute for a good old‐fashioned hot water bottle.

I love hot water bottles and have fond memories of watching my mother go through the routine of filling them every night. I hope you enjoy yours too! 

I’ll be back next time with some ideas for a cozy blanket to step onto when you wake up each morning. Until then, I hope your hot water bottles keep you toasty warm.

Happy Knitting!
​
Moira

---

For information about any of the patterns featured here or our
Reversible Knitting Stitches book, ​please click the Patterns tab above.

For more blogposts & knitting notes
​please see the index list on the right of this page ---->

---

<--- Previous Post: ​How long can you wait?

Next Up: A rug for every room --->