Every bag of flour, may it be in a 25Kg sack or just a couple of pounds has an expiration date. But you can shorten or lengthen its life depending on how you store it. I started researching for this article to see the tricks for extending the life of your flour, but I didn’t expect these tricks to work as well as they did! Here is everything you need to know on how to store flour to answer the question of how long can you store flour until it goes off.
The best way to store flour depends on how long you’re planning to store it. For the short term, using an airtight container, but leaving it in its bag at room temperature will do the job well in most cases. For mid-term storage, use airtight mylar bags. While for long-term storage, either put them inside the freezer or use vacuum-sealed bags.
So why does flour go off in the first place? Well, wheat flour is composed of the grain’s bran, germ, and endosperm. As the flour sits around, it loses moisture from the germ through evaporation. The shelf life is directly linked to how much moisture remains inside the three components. When too much is lost, the flour becomes damaged and stale.
But it’s not just moisture. Its storage environment plays a pivotal role in shelf life retention as well. In a humid climate, flour turns bad at a faster rate than in dry areas. That being said, there are other factors that cause the flour to be bad:
The breakdown of nutrients in the flour triggers a chemical reaction known as oxidation, caused by oxygen interacting with the flour. Flour oxidation makes natural oils found in whole grain flours turn rancid. This changes their flavour and makes them stale or spoiled. Because of this, old flours not only lose a lot of nutritional value but also taste terrible. To lower the effect of oxygen, keep flour sealed.
As humidity causes the flour to absorb moisture, it can lead to the formation of mould. You may not even know something is wrong by looking at aged flour, but if it has a rancid aroma, it’s gone off! To avoid mould, keep flour in a dry area.
Grains are the natural habitat for bugs and other insects that lay and hatch eggs. The most common one is the flour fly or weevil, they love flour! These insects can infiltrate your flour making it turn bad and taste terrible. Once these guys take hold, they are very hard to get rid of! I almost got sacked from a job because of these guys (not that it was really my fault) so I know how much of a pain they are! It’s common to get the odd one or two now and again, it’s often a case of sifting them out.
If you have badly sealed doors either get them sealed or store your flour as far away as possible. If you live near fields where bugs are already common it’s especially important to keep windows shut and areas wiped down from flour dust to prevent attracting the bugs.
Flour is an odour sponge that absorbs smells that are near. For example, storing flour next to garlic means your goods baked goods will be likely perfumed with garlic too. Also, if the flour is stored close to cleaning products, they may ruin it too.
So now that we know why our flour goes bad, let’s discuss how long it lasts. So you know… you’re not playing guessing games in the kitchen. The shelf life varies depending on the type of flour.
The chart below will give you a rough idea of how long the different types of flours will last. As you can see whole grain flour has a shorter life than white flour. This is because whole grains contain the wheat germ which becomes rancid quickly.
|Flour Type||Room Temperature Pantry|
|Whole-Wheat Flour||3-6 months|
|Cake Flour||6-9 months|
|Bread Flour||4-9 months|
|Rye Flour||3-6 months|
|Self-rising Flour||4-6 months|
|Oat Flour||1-3 months|
|Barley Flour||2-3 months|
|Gluten-Free or Alternative Flours(banana, buckwheat, coconut, nuts, rice, etc.)||2-5 months|
There are many ways to store fresh flour that you can use to keep your flour. Some are designed to keep flour long term, other flour storage methods take up less space and resources.
When storing flour for a couple of months for standard use. You can just let it sit in a pantry or somewhere that’s dry, cool and dark. Flour kept for a short time can be left in its bag. Others decant into 5-gallon containers as there’s less chance of getting flour dust all over the place when making bread. See 5 gallon containers on Amazon
For storing flour for more than a few months, transfer it to an airtight container food storage container with a tight seal so that no moisture or air can get inside. This will prevent your flour from turning bad and slows oxidation.
Mylar bags with oxygen absorbers are excellent. If you are worried about bugs, or for some extra keeping quality, you can put them inside the fridge. See Mylar bags with oxygen absorbers on Amazon
Storing flour for several months, a year, or even longer is still possible. You’ll want to keep your wheat and grains tasting as fresh as possible. Placing your bags or containers of flour in the freezer is a great solution. Leave the flour out until it’s reached room temperature before using it.
If you're planning on storing your bags of flour in the freezer for a long time, remember to leave room for the flour to expand. This is because some of the water will evaporate inside and cause moisture build-up in the container.
You can also transfer the flour to a vacuum-sealed container. This will prevent air from interacting with the product inside. As some vacuum-sealed bags are not food-safe, if you’re not sure, it’s best to pour the flour into a food-safe bag, push out as much air as you can, and then into a bag to vacuum seal. See vacuum-sealed bags on Amazon. The flour will keep for ages with these methods, sometimes as long as two years!
A 25Kg bag of flour is going to fill a lot of small bags, which can be expensive and not great for the environment. Putting it in the freezer is also going to take up a lot of premium space. Most bakers combat this by storing ½ or ⅓ of their flour in a long term solution. The rest can be kept in a cool place.
If you notice that your flour has discoloured, become mouldy, smells rancid, feels wet or the bread you make has a lower rise; your flour has most likely gone off. If you have ever found a bag of whole-grain flour in the back of the cupboard you can probably relate! See my how to tell if flour has gone bad article for more information.
In this article, we’ve answered the question of how long can you store flour and the best storage methods to increase its life. How do your findings compare? Let me know in the comments below and if you have any flour storage questions, drop them there and I’ll get back to you.