Author Topic: Onion storage  (Read 214 times)

Offline galina

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Onion storage
« on: February 24, 2014, 08:47:06 AM »
I read elsewhere about stronger flavoured onions storing for longer than mild flavoured ones.  That was new to me, but actually that is exactly what is happening with my lovely Red Florence onions, which really only store into autumn.

An interesting snippet from a HDRA/Garden Organic lecture (which I can confirm from subsequent own experience) is that in order to store onions for as long as possible, you can either

....... keep them cool and dry
......  keep them warm and dampish. 

The ones I put on top of the kitchen cabinets (warm and damp) do indeed last as long as the others and they are immediately to hand when I do the cooking.

Offline Big Gee

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Re: Onion storage
« Reply #1 on: February 24, 2014, 12:49:38 PM »
It's the sulphur content in an onion which is the biggest dictator in an onion bulb's ability to store well (I think I've mentioned that in another post on this forum). Guess what makes onions 'strong' flavoured? Yep SULPHUR. onions grown in soil with a high sulphur content store better than the same variety grown in low sulphur content soils. It's also the reason why onions from certain areas taste milder or stronger than onions from other areas.

The accepted wisdom is that onions store better if they are not in contact with one another (hence why they tend to store better in ropes rather than in net sacks). As we are trying to store the onion bulbs during their normal dormant period the natural conditions for a dormant period (which is winter) should be replicated as far as possible. So they need a cool environment that's dark but dry. Garages are excellent for the job because they are also airy. Warm & damp (high humidity) areas are not recommended, neither is a storage area that exposes them to sunlight.

A few years ago we had a tumble dryer installed in the garage. Every year the onions that were stored in the garage would tend to go soft & often mouldy. The cause appeared to be the warm damp air from the dryer. Once the air was saturated with a high water content and the dryer was switched off that high humidity cooled and that's what caused the mould to be encouraged.

The dryer was relocated to the kitchen and from then on the onions went back to their normal storage life. Dahlia tubers react in nthe same way - as do potatoes of course. A cool but frost free garage that's dark & airy is the ideal environment for storage of tubers and bulbs.

However it's the sulphur content of onions that has the greatest effect on their storage life.