root cellar for storing potatoes

How To Make Potatoes Last Longer

Many articles revolve around getting our potatoes to grow to the best of our ability, but once we have got our crop to grow well and have harvested them, if we don’t provide them with the correct environment during storage they will quickly go bad.

I will provide a checklist of points along with a brief explanation of why it exists for you to follow. This should help you ensure your potatoes are being stored in optimal conditions with the focus on how to make potatoes last longer.

Many people don’t realise that potatoes are 75-85% water, this is something we need to keep in mind when storing them. The spongy soft potato you find in the back of the cupboard with long sprouts is massively dehydrated compared to the day it was dug from the field.

Checklist of points to make potatoes last longer in storage

Wherever you currently store your potatoes may change by the time you finish reading this list. The following list is about ideal scenarios – you will have a better idea where you should store your potatoes in your home by understanding the type of environments potatoes prefer to be stored in.

Keep the storage temperature between 8 – 10 degrees centigrade (46F-50F)

Potatoes are a living organism – even after harvesting from the soil. Potatoes respire (they convert sugar and starches to carbon dioxide) this causes them to dehydrate and shrivel up over a period of time.

The speed at which respiration occurs is dependent on the temperature of the potato – the higher the temperature the faster they respire. You may ask why not store the potatoes at an even lower temperature so they will last even longer – while this may be true – you will be altering the usability of the potato.

When a potato is stored at a temperature below 8-10C they convert their starches to sugar, this alters the taste and the useability of the potato. It can no longer be used for frying – this can be seen when a chilled potato is fried for chips – the flesh turns dark in colour (black) in the fryer.

Monitoring the temperature of your store closely is important to keep it in this 8-10 zone so the potato can be used for all types of cooking, yet will store optimally for the longest time possible.

Ensure there is airflow through the store

There are a number of important points why airflow is needed through your potato storage area. We mentioned above that potato respire – when potatoes are first harvested this respiration is greatest.

If there is no airflow through the store it will cause the potatoes to sweat. Wet conditions with no airflow promotes mould to grow which will rot your potatoes if left long enough.

The other reason to have airflow through your store is after potatoes are harvested they may be wet – if you put wet potatoes into a store with no airflow they will not dry out – again leading to problems with rot.

The volume of air does not need to be massive – just a vent on each side of the store to let air pass through. A single vent does not work – there needs to be a minimum of two vents for air to pass through.

An important point id like to mention here is deciding where you get this airflow from. If the air can be obtained from colder sources such as a shaded outdoor area rather than airflow from inside the home this is much better as it will usually be colder.

Ideally, you want the air source to be around the same temperature as your ideal storage temperature of 8-10C. Otherwise, if your supply air is 20C your potatoes in the store will end up at 20C also.

The store should be dark and have no direct sunlight

If a potato is left out in daylight for more than one day it will turn green – it will then be unusable and unsafe to eat. This greening of the potato is also known as sunburn – it causes the potato to produce a chemical called solanine which can make humans sick if eaten in large quantities.

Your store needs to be able to block out light for this reason – also it will be much easier to regulate a stable temperature without the sun shining in and heating it up.

Modern long term potato store
Modern long-term potato stores have no windows, are temperature controlled, and have good airflow through them.

Store your potatoes in containers that wont sweat the potatoes

Obviously you’ll keep your potatoes in bags or some other container within your store. It is important that the container will not promote sweating or be airtight such as plastic bags.

Many supermarkets sell potatoes in plastic bags – but these have small holes in them to allow the potatoes to breathe and help prevent moisture build-up. I would advise you not to store your potatoes in plastic bags – choose a breathable natural fabric such as hessian, which will also help block out light also.

Or you could choose to store your potatoes in slatted wooden crates – these are also great as they allow plenty of airflow through them, block out some light, and will stack neatly in your store.

Summary

To summarise – potatoes will last longest if they are kept in breathable containers made from natural materials -such as hessian bags or slatted wooden boxes. The store should be dark inside at a temperature of 8-10C (46-50F) with an airflow passing through it. The closer to the ideal storage temperature you can get your airflow from the better.

The reason people kept vegetables in cellars under the ground years ago was that they were dark, cold (more stable temperature under the ground) and the airflow through the cellar was obtained from the outside air which was colder than the warm air circulated through a house.

Below are links to some of the products I discussed in my article:

Breathable hessian potato storage bags

Indoor/ Outdoor temperature sensor