I’m lucky enough that I can bake frequently and that I can also use a lot of flour with my bread baking students.
This means that the flour rotation in our little kitchen bakery is quite high and I very rarely have flour that has gone bad. But how can you tell if your flour has gone bad?
Can flour go bad? The quick answer
Yes, both bread or cake flour can go bad if it’s not stored properly or just too old. Flour can be used well after it’s sell by or use by date. As long as the flour is not off, it can be used?
How to (definitely) tell if flour is off? The fault prooved answer
The easiest way to tell if flour has gone bad is to taste it. If the flour taste bitter, it’s off. It doesn’t matter whether the flour is still within it’s sell by date or has been stored well. If it’s bitter it’s off and you shouldn’t use it.

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How I learned how to tell if my flour is bad
When I was growing up, my grandmother would always bring us large sacks of flour that she was given as part of an annual payment from a local farmers co-operative that was renting her farm fields for growing flour grains and other crops.
Having lots of flour was great because we could bake whenever we wanted, but it also meant that sometimes we just couldn’t get through the whole lot and the flour would go off.
My mum showed me how to test the flour and I used to do this every time before I started to bake anything. The sacks of flour were in non-commercial packaging, so was no sell-by date or use by date on them.
There are several ways of checking whether the flour is still fine to use, but I always use the following test to make sure.
How to tell if your flour has gone off?
When I bake for myself I don’t tend to bother with sell by dates or use by dates as these are just guidance for flour and it depends more on how you store it.
To test whether my flour has gone off or not I simply taste a bit of flour (just lick your finger, stub it into a bit of flour and taste it). If it tastes bitter, the flour is off.
If you don’t fancy licking and tasting your own flour, let’s have a look at some other ways you can tell if your flour has gone bad or not.
Most types of flours don’t have much of a taste, which is what you are looking for. There are some flours, like for example lupin flour, that might taste slightly earthy, but that’s only natural flavour.
Other flours might have a slight taste based on what they are made of. For example, potato flour will have a faint potato taste and the same goes for rice, oats or chickpeas flour. However, none of these flours should taste bitter.
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Check the sell by – use by date
The obvious thing to do is to check the date on the packaging.
If the flour is way beyond its sell-by or use-by date, then it’s likely to be off. I would still go through the rest of the checks, including the taste test, because I’ve had flours that were slightly out of date and they were still perfectly fine to use.
Check the outer packaging for any signs of fine webbing, holes or discolouration
If you get flour weevils inside your flour (small white flour beetles) the first sign that they are inside the package is a fine webbing at the bottom of the flour bag (outside) and also when you open the flour bag.
If you do find un-invited guests in your flour, I wouldn’t bother using it. It’s not just the beetles that you’ll find inside, it’s also their faecal excrements, which you can’t really get rid of even if you put the flour through a sieve.
Check for any other things that could spoil your flour (mould, wetness)
If you store your flour in an environment that’s too warm and moist, you might end up with mould growing inside your flour bag. Since mould spores spread really quickly, I wouldn’t use this kind of flour for baking.
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Check the colour of your flour
Plain, white, self-raising, gluten free or strong white bread flour is usually white or slightly off white. When the flour goes off, the colour can change to slightly grey or brown colour.
Check the smell of your flour
Sometimes you can smell that your flour has gone off as it will have a very rancid kind of smell. Normally flour doesn’t smell of much, so if it does have a strong smell, it’s probably not a good sign and your flour might be off.
Taste the flour
If you are still in doubt and you have gone through the process above and everything looks fine, the last resort is to taste the flour.
Taste only a tiny bit from the tip of your finger, if the flour has no taste, it’s fine, but if it tastes bitter it’s off.
Can you use flour that’s off?
If the flour is off it tastes bitter. It means that the flour has gone rancid and can’t be used for baking.
No matter how you would use that kind of flour, the bitterness will always come through. Believe me, I tried it and no matter how much sugar or chocolate you add to your cake, the bitterness will be always there.
If the worse comes to worse and you don’t have any other flour to use for your cooking or baking, you can still use flour that’s gone off, but it won’t taste nice and you might even get stomach ache – depending on how sensitive your digestive system is.
Spoiled flour is usually not poisonous, but the bitter flavour is impossible to mask in cooking or baking and it might spoil the rest of your food.
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