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December 31, 1898, 



GARDENERS' 



MAGAZINE. 



869 



Cold Storage of Fruit. 



The Technical Education Committee of the Kent County Council appointed 

 some time since a sub-committee for the consideration of the subject of cold 

 storage as applicable to the preservation of fruit and vegetables, and this sub- 

 committee consisted of Mr. E. Hesketh (chairman), Mr. W. W. Berry, Mr. W. 

 Chambers, Mr. R. Mercer, and Mr. A. T. Waring. 



At a recent meeting the committee, in view of the great and growing 

 importance of the question of cold storage, resolved that the valuable interim 

 report of their superintendent of horticulture, Mr. W. P. Wright, upon the ex- 

 periments conducted by the sub-committee at Messrs. Hall's Engineering Works, 

 Dartford (through the kind interest of Mr. Hesketh), should receive the fullest 

 publicity, and in accordance with such resolution this report has been sent to us 

 for publication, and is given herewith : — 



A courteous intimation from Mr. Everard Hesketh, received in July last, that 

 the experiments in the cold storage of fruit, which had been necessarily suspended 

 during last year, had been resumed, was received by me with much interest. Mr. 

 Hesketh's letter was prompted by his kind recollection of the fact that I had 

 derived much pleasure from a chance visit many months previously, and by his 

 correct assumption that any important step bearing on a great industry, with 

 which I was professionally connected, would command my attention. I gladly 

 availed myself of his invitation to pay an early visit to the works, and as my call 

 coincided with an impending meeting of the committee I drew up, at his request, 

 a brief report of what I saw. The Immediate result of this was the reception of 

 your instructions to pay weekly visits to the cold chambers with a view to regular 

 reports stage by stage. The duty thus laid upon me I have striven to fulfil carefully 

 and faithfully, paying due regard to the desirability of giving minute attention to 

 detail, and to the imperative necessity of setting down with the utmost accuracy 

 the exact condition of the fruit as I saw it from week to week. 



My conception of the first requirement of the task which you entrusted to me 

 was that I must approach it with a mind absolutely f ee from prejudice either for 

 or against the work in hand, and this seemed to me the more pre-eminent from 

 the magnitude of the issues at stake. As I understand your object in these 

 experiments, it is to ascertain whether any practical means exist for assisting 

 British cultivators to secure a porcion, at least, of the millions which we expend 

 on foreign fruit and other soil products. Above everything, therefore, all tests, and 

 all records of such tests, must be governed by one consideration alone — accuracy 

 and truth. Whether, therefore, the facts noted are or are not in consonance with 

 the trend of your endeavours, I have held it my duty to set them down, so that 

 those interested may not on the one hand suffer from the lack of useful infor- 

 mation, nor on the other be misled by careless or partial observations. 



The Cold Chambers. — These number three. Their base is on the ground 

 level of the buildings, and glazed apertures are provided there for reading the 

 thermometers, which are suspended within, the temperatures being thus recorded 

 without any opening to the outside air. An entry, however, can only be effected 

 by means of trap-doors, kept locked, in the floor of the loft above. Internally 

 the arrangements are simple, but adequate. A series of staging, tier above tier, 

 consisting of wire shelves, supported by a wooden framework, is erected on 

 each side of a central path. The walls, floors, and ceilings are well insulated, 

 and in each chamber, close to the insulated walls, are two brine walls or flat 

 tanks, through which the cold brine is circulated, and by their means the tempera- 

 ture is lowered to any desired degree. There are spaces for the circulation of 

 air at the front and back of the brine walls, and a trough is fixed under each to 

 convey moisture condensing on them to a collecting pan. 



The Experiments. — In each chamber the fruit is stored under three different 

 conditions : (1) exposed on the shelves; (2) enveloped in grease-proof paper ; (3) 

 surrounded or covered by cotton- wool. The last two conditions are supplied with 

 a view to checking the loss of weight from the fruit by evaporation, which it was 

 anticipated would take place. The increased weight of the air of the chambers 

 as it is cooled by contact with the cold brine walls causes a downward current 

 over them, and, of course, a corresponding upward current at other parts of the 

 chambers. There is, therefore, a constant circulation of air maintained. These 

 incessant air currents passing over the surface of the fruit extract moisture from it, 

 and hence the use of the interposing materials to check this. 



Strawberries — In dealing with the different fruits experimented with I 

 will first of all take the strawberry. It was nearly at the end of the season of this 

 fruit, namely, on July 23, when my visits began. I could, therefore, only report 

 on fruit placed in previously. The temperature of No. I chamber was maintained 

 at 42 degrees, of No. 2 at 36 degrees, and of No. 3 at 30 degrees. I found a very 

 striking difference in the condition of the fruit, all of which had been put in a 

 fortnight before, namely, on July 8. That in No. 1 was mouldy, although the 

 fruit enclosed in pap^r was hardly so bad as that exposed and that in wool. About 

 the fruit in No. 2 my remarks were : " Exposed fruit a little mouldy, but not so 

 bad as in No. 1 ; wool fruit slightly affected, but very little, flavour good ; paper 

 fruit sound, flavour good." With regard to No. 3, the state of affairs was 

 better. In each experiment the fruit was quite sound and good. It was 

 not frozen, in spite of the temperature of 30 degrees, but a slight 

 toughness of the flesh was observable. The exposed fruit, though sound, was dull 

 and had a glazed appearance. That in paper was good and fresh. Weekly visits 

 were subsequently paid. So far as the highest temperature was concerned the 

 experiment was at an end, as the fruit was spoiled: The intermediate tempera- 

 ture gave little better results, and after the third week of storage I had to report 

 that the greater part of the fruit was decaying. In the 30 degree chamber, how- 

 ever, a very different state of affairs prevailed. At the end of the third week I 

 was able to report : " The exposed fruit in No. 3 is all sound, but dull and 

 flabby-looking, the flesh tough ; the fruit in wool is sound, clear, and fresh, the 

 flavour excellent ; the fruit in paper is sound, but dull, and the flesh rather tough. 



The strawberry experiments may be epitomised as follows : (1) The fruit cannot 

 be kept long in a temperature of 36 degrees or upwards ; (2) it can be kept for 

 three weeks at least in a temperature of 30 degrees ; (3) it is necessary to surround 

 the fruit with cotton wool, or, in the case of fruit in sieves, to place a pad of that 

 material over the top. If this precaution is not taken the iruit, though sound, 

 becomes dull and loses the fresh, inviting appearance which is so important when 

 it is offered for sale. 



Black Currants.— A series of experiments with these began on August 10, 

 and weekly observations were made. In No. 1 chamber the temperature was 

 36 degrees, in No. 2 30 degrees, and in No. 3 26 degrees. At the end of ten 

 days the fruit was sound, fresh, clear, and in good market condition. From that 

 time it began to shrivel, there being little to choose between the chambers, or the 

 fruit exposed, in paper and in wool, respectively. Inasmuch as the value of black 

 currants may rise if good fruit can be held over a glut lasting only for a few days, 

 I was disposed to regard this experiment as a qualified success rather than an abso- 

 lute failure. Nevertheless, the fact that the fruit could not be kept from shrivelling 

 for a fortnight was a disappointment. Subsequently the idea occurred to me to 



have some of the fruit removed from the store and kept for a few hours in a 

 normal temperature, thus subjecting it to the same conditions as would prevail in 

 the case of fruit en route from farm to market. This was done at the end of the 

 third and again at the end of the fourth week It elicited a curious, interesting, 

 and instructive fact, namely, that the fruit when almost as wrinkled as dried shop 

 currants will plump and freshen to such a degree as to be marketable. This was 

 especially the case with black currants that had been stored in market sieves 

 peered with a wad of cotton wool. After a fortnight's storage the temperature 

 in No. 2 was raised to 32 degrees, and this seemed to give the best results of all. 



Red Currants.— The experiments with this fruit were an unqualified success. 

 No. 1 chamber was maintained at 36 degrees. No. 2 was started at 30 degrees, 

 and raised after a fortnight to 32 degrees. No. 3 was started at 26 degrees and 

 raised to 30 degrees. The fruit was stored on August 10, aqd was examined with 

 great care for six consecutive weeks. To begin with, 26 degrees and even 30 

 degrees were found to be too cold. With the former the fruit froze and with the 

 latter lost clearness. Excellent results were, however, got in chambers 1 and 2. 

 The fruit remained perfectly sound for six weeks, and when exposed lor sixteen 

 hours to a normal temperature maintained its freshness. The fruit surrounded by 

 paper was better than that exposed and also superior to that in wool ; indeed, it 

 was difficult to distinguish it from freshly-gathered fruit. Wool seemed to 

 encourage bleeding, and the ideal conditions seemed to be (1) a temperature of 

 32 degrees to 36 degrees, (2) a covering of paper to prevent contact with the cur- 

 rents of air constantly flowing. 



Cherries. — The temperature of No. 1 chamber was kept at 42 degrees, 

 of No. 2 at 36 degrees, and of No. 3 at 30 degrees for this fr at. It had been 

 in store a fortnight when I began my visits. In No. 1 the exposed fruit was 

 sound but dull ; the fruit in wool was not only sound but quite fresh and clear ; 

 that in paper was somewhat mouldy. The end of the third week found all the 

 fruity decaying and mouldy. A much better condition of affairs existed in the inter- 

 mediate chamber. At the end of the third week all the fruit was.quite sound. A 

 defect of the fruit exposed (and in a lesser degree that in paper) was that it was 

 dull. The fruit covered with wool, however, was not only sound, sweet, and 

 jui^y, but fresh and clear. The same condition was observable at the end of the 

 fourth week. After that the fruit began to wrinkle. Almost the same remarks 

 apply to No, 3. At the end of a month the fruit was sound, but flabby and dull 

 exposed and in paper ; covered with wool it was clear and fresh. 



Plums. — A series of experiments with the four varieties, Orleans, Green- 

 gage, Sultan, and Diamond, began on August 24, and later on Monarch, Victoria, 

 and Coe's Golden Drop were put in store. The first four only are dealt with 

 now. They were placed in temperatures of 36 degrees, 32 degrees, and 30 degrees, 

 respectively. The fruit was removed from the chambers on November 4, and 

 examined on the following morning, after being exposed to the normal temperature 

 for about sixteen hours. The greengages were all perfectly sound and of excellent 

 market appearance, except that the fruits which had been on the upper parts of 

 the heaps were a little wrinkled. So luscious and good did they seem, both 

 internally and externally, that it was a disappointment to find that they tasted 

 distinctly of paint. They had been put in before the smell of paint had passed 

 off. The fact, however, does not destroy the significance of the experiment — ■ 

 namely, the successful keeping of greengages for ten weeks. With respect to 

 Orleans, Diamond, and Sultan, all three were much inferior. None of these can 

 apparently be kept good for ten weeks. If stored just before they are quite soft 

 they will remain in good condition for a month or six weeks. We had them 

 exposed on the shelves, but I think they would have been better covered with a 

 pad of cotton wool, and I am led to this conclusion by having observed that the 

 fruit at the lower part of the heap3, and protected, to a certain extent, from 

 contact with the air by that above, was fresher and fuller than the upper layer. 

 As regards temperatures, the highest was the least suitable. There was little to 

 choose between the others, and 32 degrees may be regarded as about right. A 

 fuller report of the plum experiments will be made, 



Tomatos. — After six weeks' storage, the fruit from No. I chamber (tempera- 

 ture 36 degrees) proved, on being cut open, to be quite good. The leaf-stalks 

 had, however, decayed, and at the points of their attachment the fruits were 

 externally blackened. This gave a fallacious appearance of decay. The blackening 

 was merely a local, or surface, trouble, not extending to the body of the fruit ; 

 nevertheless, appearances play so important a part in market produce, that it 

 would seem to be advisable for the stalks to be removed when the fruit is stored. 

 The samples, which had been carefully chosen, showed that the fruit which was in 

 the best condition at this examination was that gathered just in advance of 

 softening for dead ripeness, i.e., fruit that had coloured, but was still firm. 

 Further tomato trials are in progress. Fruit in various stages of .ripening is under 

 examination in lower temperatures, and particulars will be given in the final 



report. 



An Expert on Cold Storage. — In view of the fact that doubt may be 



felt as to whether the cold storage of fruit has commercial advantages in this 

 country, it will be well to give the opinion of Mr. W. N. White, a great Covent 

 Garden dealer. He has stated to an interviewer his conviction that, 11 with 

 proper refrigerating facilities, English fruit might almost drive foreign produce 

 out of the market. Most English fruit enjoys a very short season— from six 

 weeks' to two months' duration. All the fruit becomes ripe about the same 

 time ; the growers throw it on the market ; the buyers become masters of the 

 situation, and if it were not for the jam -makers the stuff could not be sold at 

 all. If there were adequate cold storage, one-third more English fruit cjuld be 

 sold at 25 per cent, more money." 



General Remarks.— The following suggest themselves as important points : 

 (i) The fruit must be placed in store in advance of dead ripeness. This is parti- 

 cularly the case with strawberries. Fruits that are fully ripe will keep for some 

 time, but lose surface freshness, becoming seared and unsightly. (2) It is useless 

 to put injured fruit in store. Cherries pecked by birds soon go off and other fruits 

 impaired in any way will not keep. To achieve success the fruit must be sound. 

 (7) The fruit should be covered or surrounded with cotton wool. It was 

 observable that that so treated retained its freshness much longer than that left 

 exposed. (4) The chambers must be kept dry, and close-fitting doors are 

 necessary, otherwise damp and gritty impurities find entrance. We had a little 

 initial trouble with No. 2 on this account, and after it was remedied the fruit kept 

 much better. (5) All decaying or impure matter must be rigidly excluded. The 

 Dartford chambers (which are open to the inspection of anyone interested) are 

 models of cleanliness. Nevertheless, some fruit placed in one before the smell of 

 paint had quite disappeared tasted unpleasant. 



Future Experiments. — The work successfully undertaken with early 



fruits is being continued with later kinds. We have in store some of the 

 popular early market apples, such as Worcesters and Duchess's Favourite, such 

 well-known oears as Williams, Conference, Fertility, Doyenne du Cornice, 

 Pitmaston Duchess, and Beurre Hardy ; also grapes, peaches, and tomatos. In 

 the main, attention is being concentrated on early sorts that will not keep under 



