The Chemistry of Cookery

by W. Mattieu Williams

As ordinary thermometers register but little above 212°, and laboratory thermometers are too delicately constructed for kitchen use, I requested Messrs. Davis & Co. to construct a special thermometer for testing the temperature of heated fat. They have accordingly made an instrument that answers the purpose very well. It is like a laboratory thermometer, i.e. a glass tube with long bulb and the degrees engraved on the glass itself, but the bulb is turned at right angles to the tube, so that it is horizontal when the tube stands perpendicular, and lies under a stand just above the level of the bottom of the kettle. The instrument thus stands alone firmly, with its bulb fully immersed even in a very shallow bath of fat.

Gouffé says: ‘Fat is the best for frying; the light-coloured dripping of roast meat, and the fat taken off broth are to be preferred. These failing, beef suet, chopped fine and melted down on a slow fire, without browning, will do very well; when the bottom of the stewpan can be seen through the suet, it is sufficiently melted.’ He is no advocate for lard, ‘as it always leaves an unpleasant coating of fat on whatever is fried in it.’ Olive oil of the best quality is almost absolutely tasteless, and having as high a boiling point as animal fats it is the best of all frying media. In this country there is a prejudice against the use of such oil. I have noticed at some of those humble but most useful establishments where poor people are supplied with penny or twopenny portions of well-cooked, good fish, that in the front is an inscription stating ‘only the best beef-dripping is used in this establishment.’ This means a repudiation of oil.

On my first visit to Arctic Norway I arrived before the garnering and exportation of the spring cod harvest was completed. The packet stopped at a score or so of stations on the Lofodens and the mainland. Foggy weather was no impediment, as an experienced pilot free from catarrh could steer direct to the harbour by ‘following his nose.’ Huge cauldrons stood by the shore in which were stewing the last batches of the livers of codfish caught a month before and exposed in the meantime to the continuous Arctic sunshine. Their condition must be imagined, as I abstain from description of details. The business then proceeding was the extraction of the oil from these livers. It is, of course, ‘cod-liver oil,’ but is known commercially as ‘fish oil,’ or ‘cod oil.’ That which is sold by our druggists as cod-liver oil is described in Norway as ‘medicine oil,’ and though prepared from the same raw material, is extracted in a different manner. Only fresh livers are used for this, and the best quality, the ‘cold-drawn’ oil, is obtained by pressing the livers without stewing. Those who are unfortunately familiar with this carefully-prepared, highly-refined product, know that the fishy flavour clings to it so pertinaciously that all attempts to completely remove it without decomposing the oil have failed. This being the case, it is easily understood that the fish oil stewed so crudely out of the putrid or semi-putrid livers must be nauseous indeed. It is nevertheless used by some of the fish-fryers, and refuse ‘Gallipoli’ (olive oil of the worst quality) is sold for this purpose. The oil obtained in the course of salting sardines, herrings, &c., is also used.

Such being the case, it is not surprising that the use of oil for frying should, like the oil itself, be in bad odour.

I dwell upon this because we are probably on what, if a fine writer, I should call the ‘eve of a great revolution’ in respect to frying media.

Two new materials, pure, tasteless, and so cheap as to be capable of pushing pig-fat (lard) out of the market, have recently been introduced. These are cotton-seed oil and poppy-seed oil. The first has been for some time in the market offered for sale under various fictitious names, which I will not reveal, as I refuse to become a medium for the advertisement of anything—however good in itself—that is sold under false pretences.

As every bale of cotton yields half a ton of seed, and every ton of seed may be made to yield 28 lbs. to 32 lbs. of crude oil, the available quantity is very great. At present only a small quantity is made, the surplus seed being used as manure. Its fertilising value would not be diminished by removing the oil, which is only a hydro-carbon, i.e. material supplied by air and water. All the fertilising constituents of the seed are left behind in the oil-cake from which the oil has been pressed.

Hitherto cotton-seed oil has fallen among thieves. It is used as an adulterant of olive oil; sardines and pilchards are packed in it. The sardine trade has declined lately, some say from deficient supplies of the fish. I suspect that there has been a decline in the demand due to the substitution of this oil for that of the olive. Many people who formerly enjoyed sardines no longer care for them, and they do not know why. The substitution of cotton-seed oil explains this in most cases. It is not rancid, has no decided flavour, but still is unpleasant when eaten raw, as with salads or sardines. It has a flat, cold character, and an after taste that is faintly suggestive of castor oil; but faint as it is, it interferes with the demand for a purely luxurious article of food. This delicate defect is quite inappreciable in the results of its use as a frying medium. The very best lard or ordinary kitchen butter, eaten cold, has more of objectionable flavour than refined cotton-seed oil.