Have you ever thought about the concept of sustainability and the oven ready frozen chip?

The oven ready frozen chip fits neatly into the convenience food sector, but ask yourself "if it's for my convenience, whose inconvenience is it?"

Everything we do has an effect on our environment and it spreads much further than just going to the supermarket for the weekly shop.

Some of the impacts we can consider are the energy and packaging aspects, If we must have chips we can make the comparison between old fashioned home made chips and convenience oven ready frozen chips

Where do we start?

I suppose we start somewhere near the red sea where the oil for the diesel fuel for the tractor used to plough the fields originates.

Some of this oil could possibly be used to make the fertilizer and the pesticides, to ensure the best possible yields per hectare of the crops and all the energy inputs, not to mention the fuel for the oil tanker transporting the crude oil to the UK refinery.

More energy is then used to convert the crude oil into the required products. This is then transported to the various depots for distribution.

Eventually the diesel fuel makes its way into the tractors fuel tank to be used in such a way that 3/4 of the energy content of the fuel is thrown away (what a way to run a civilisation).

The tractor engine is about 25% efficient. Once the field is prepared the seed potatoes are planted. These are usually transported form Scotland so we have another energy input.

Then we wait for the growing to start - solar energy and rain create the correct conditions for the seed potatoes to push forth spring growth.

Various applications of agro chemicals are applied to the crop during the growing season along with copious irrigation to maximise the crop yield.

Eventually the plants are sprayed with diquat to kill the green part of the plant to control tuber size and moisture content.

The crop is then lifted by machine and transported to the grading station. Here the process changes.

The potatoes are either packed for sale in paper sacks 25kg, or smaller polythene bags, or transferred to the food processing plant.

At the food processing plant the potatoes are washed and peeled in such a way that the eyes are not a problem, this process results in muddy water and potatoes residues.

The potatoes then go to the chipping section (crinkle or straight) short or thin chips are discarded, the chips are then blanched (steamed) sprayed with oil and frozen and on to the weighing and packaging machine.

The bags of chips are boxed and put into cold storage.

From here on the humble frozen chip is a passive energy consumer since its environment must be kept at well below freezing point right from warehouse to home freezer, it goes like this:
Factory cold store to
Frozen food transport to
Supermarket cold store of distribution centre to
Refrigerated display cabinet to
Domestic transport to
Home freezer to

But, they take longer to cook than home made chips since they are frozen to start with and take extra heat to bring them up to the temperature of home made chips.

All we need for our sacked potatoes is a dry cool warehouse, transport is simply a curtain sided truck and storage and display at the retail outlet with possible illumination at the point of sale.

So to save a few minutes in preparation time at home, we have caused an entire factory to be at our bidding and all the effluents associated with it and all the energy used to keep the frozen chip frozen right up top the point of cooking.

Sack of potatoes - 18p/kg
Oven ready chips - 54p/kg
Crisps - £8/kg

Mike Riley


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