POINTS IN BUTTER-FACTORY MANAGEMENT UNDER HOME SEPARATION.

New Zealand Journal of Agriculture, Volume XIII, Issue 1, 20 July 1916, Page 17

POINTS IN BUTTER-FACTORY MANAGEMENT UNDER HOME SEPARATION.

G. M. VALENTINE,

Dairy Instructor, Auckland.

The change that has taken place in many districts in New Zealand from the whole - milk system to home separation has necessarily been accompanied by alteration in the methods of handling. The question arises whether those methods are all they should be. Among factory-managers themselves considerable difference of opinion exists on the various points involved, and it is with a view of helping to elucidate these points that these notes have been written.

While one factory shows a moisture-content of 13-30 per cent, and an overrun of 23 per cent., another has 14-29 per cent, of moisture and an overrun of 16-90 per cent. Obviously both are wrong. As the actual unavoidable losses in a well-equipped homeseparation factory are reduced to a minimum, the largest being probably the overweight given in packing the butter, there must be serious defects in methods which bring about such results. The avoidable losses or gains are the result of mistakes in weighing, sampling, and testing of cream, and low moisture-content of butter.

WEIGHING, SAMPLING, AND TESTING CREAM.

Where milk is received a mistake of 1 lb. in weighing is a comparatively small matter, and the sampling is simple, as every can is tipped. With cream it is much more serious, as cream is relatively ten times more valuable than milk. A mistake of 1 per cent, in weighing will make a difference of approximately 1-2 per cent, in overrun either way.

To ensure correct weighing' of home-separated cream it is absolutely necessary to have every can conspicuously marked with the name or number .of the supplier and the weight of the can. The plan of substituting a number for the supplier’s name is becoming very popular, has many points of advantage, and, if painted on the can in fairly large figures, simplifies handling. Thus, 146/20 will represent the supplier’s number and the weight of the can. By having the sample-bottles numbered to correspond a stranger can go on to a receiving-platform and take .in a day’s cream without

3094.

any chance of error. The daily docket showing gross, tare, and net weights will help to prevent mistakes, and assist in tracing them if made.

Probably the plan most generally followed on a home-separation-factory platform where cream is received in wagon or truck loads is to sort out all the cans in the same rotation daily. The lids and floats are then removed, floats scraped, and the cream stirred and sampled. If thirty suppliers are represented, thirty trips have to be made to the sample-cabinet, and frequently before the last can is reached the curd has had time to settle to the bottom, resulting in a high test. .The plunger and sampling-dipper follow round the rotation, and * are dipped into a 25 - per - cent, cream from a 50-per-cent, without rinsing. The cans are then carried to the scales, weighed, tipped, and steamed. A dirty hand instead of a squeegee is still often used to scrape the floats.

About the only advantage that can be claimed for this system is that the figures are in the same rotation daily where dockets are used. The advantage is more than balanced by the greater effort required to sort out full cans than to sort out figures.

The system which appeals to me as giving the best results with a minimum of labour in a moderate-sized factory is one under which the booking-desk, scales, and sample-cabinet are as close to the receiving-vat as possible. The cans are taken as they come, placed in the scales, and the lid and float removed and scraped. The cream is weighed, sampled, graded, booked, and tipped into the vat, the can beingplaced on the steamer ready for the man washing up. Where a big pasteurizer is in use these various operations will necessarily be performed by several men, each doing his part. Under this system a smaller receiving-platform is required, and there is no unnecessary handling of full cans.

The sampling is done immediately after the cream is stirred and the sampler and plunger can be rinsed between each weighing. Steaming the cans after they are emptied is much better than rinsing, and there is less waste of cream, less handling of unnecessary water afterwards, and the work' is much cleaner.

There are still a number of factories where the sample-bottles are not numbered. The managers concerned argue that by keeping the bottles in rotation the number ng is not necessary, as no mistakes are made. As mistakes are made in those factcries where numbers are used, no further argument is necessary to prove that the same thing happens where numbers are not used. Some object that when numbers are attached the bottles are a trouble to sort out after they are 1 washed. This can be overcome by grinding a

rough place on each bottle with an emery stone and the numbers on in pencil. The bottles can then be removed for testing, and even if mixed no harm is done if corresponding numbers are written on the testing-bottles also when testing.

Various styles of sample-cabinets are in use, a chest of drawers, in my opinion, being as good as any. Each drawer can be made to represent a district, and the drawer can be used to heat the samples in when testing.

Only the highest grade of scale is good enough to weigh creamsamples, and speed must be secondary to accuracy. The scale should be sensitive to one drop of cream. The reading of the tests is now seldom done without the use of coloured oil or superfatted alcohol to level off the meniscus. The mistake of using the oil too cold is sometimes made, however. It should be slightly hotter than the fat-column —say, 145° F.

The importance of extreme care in testing cannot be too strongly urged. The supplier must trust to the factory-manager for a fair deal, and, unfortunately, testing-day is usually an extra, and to be got through with an effort. There is a good deal to be said in favour of the independent tester from the point of view both of the manager and of the supplier. A mistake of .1 per cent, in a 40-per-cent. test represents 2| per cent, of the total butter-fat, and 3-05 in overrun.

NEUTRALIZING AND PASTEURIZATION.

The only reliable system of neutralizing cream is by means of the double vat, and the vat should be of such . size that the pasteurizer will empty it in about forty-five minutes, otherwise the acidity will be found to rise before the cream is all through. The practice of tipping a few cans of cream and then adding some soda can never be relied upon to give the acidity aimed at.

Various calculations are in use to ascertain the amount of neutralizer necessary to reduce the acidity of the cream -to the desired point —all of them more or less useful as a guide, but not to be relied upon for accurate results. A change in the brand of soda, neglect of proper stirring of the cream after adding the soda, mixing the soda with hot water, and many other things, may quite upset the calculation. •

By the use of a double vat the first sections can be filled to a given mark which will approximate the same weight of cream daily. A little practical experience and tabulating of results will soon give a table of quantities of soda required to reduce the acidity to the desired point with cream varying in ripeness from

day to day; but only the frequent use of the alkaline test will show whether the result aimed at has been attained, and any variation can be corrected by the addition of a little more cream or soda. By repeating this procedure with each section of the vat alternately an even acidity can be obtained right through.

‘With a single vat such’ correct regulation is not possible. Unless the greatest care is taken the acidity of the cream leaving the cooler may be 0-4 at one stage and ’ o-i shortly afterwards; and though a sample taken from the ripening- may show somewhere near the right average acidity the quality of the butter will suffer. The point to remember is that practically the whole of the work performed 'by , the soda is done while the cream is passing through the pasteurizer, and hence no averaging-up in the vats afterwards is of any use.

The use of a neutralizer has only been made possible by the adoption of pasteurization, and it depends for success upon the same conditions which make for success with the latter process—namely, the application of heat to every particle of cream passing through the machine. When installing a pasteurizer it is a good practice to allow an ample margin over the quantity the machine is required to do. A machine with ’ a capacity of 1,000 gallons per hour will do more thorough work if only called upon to put through .750 gallons, and will do it at a less cost for steam.

The speed should be regulated so that the cream is spread over the heating - surface in a thin layer, thus ensuring the easy transfer of heat to the cream. The danger of the casein burning on and scorched flavour at high temperatures will be reduced, and a thorough utilization of the soda will result. This speed may be anything from 200 to 350 revolutions per minute, depending on the make and size, of the machine, and can be judged by the amount of cream left in the pasteurizer. A slow-running pasteurizer will have a greater body of ' cream in the machine, and though the outside which comes into direct contact with the steam may be scorched, the inner portion is not thoroughly pasteurized, and the soda will not have been completely used, which may result in soda flavour. An intermittent delivery of cream from the pasteurizer indicates that the speed is too slow. -

Better results will be obtained, and economy in fuel will result, if exhaust steam is used for. pasteurizing. , There is less danger of burning on, and an even temperature is more easily maintained, as the pressure of' steam is not so much affected by the variation of the pressure on the boiler. The exhaust should also be used for

heating water for boiler-feed and washing-up purposes. A threeway cock will make it possible to use the exhaust for both purposes.

COOLING AND THE REFRIGERATING PLANT.

Economy in cream-cooling is a very much neglected point in many factories. The first cooler should be of such a size that the cream when leaving it is not more than 4 0 above the inlet water. If this result is not obtainable the cooler is not large enough, and work will be thrown on to the refrigerator unnecessarily. The second cooler must be large enough to allow of any temperature desired being obtained by regulating the flow of chilled water. The chilled water, if lower in temperature than the ordinary water, can then be pumped back to the chilled tank. The practice of filling a vat up with cream at a temperature as high as 70° to 80° and depending on the refrigerator to cool it is altogether too expensive and disastrous to quality when handling home-separator cream. . ..

The refrigerator is perhaps the most neglected machine in the average factory. Too often there is more air than ammonia' in the system, and if free' from air the ammonia is deficient. In about nine cases out of ten where a machine is working badly air in the system is the cause, and in the tenth case it is usually a lack of sufficient ammonia. The refrigerator should be kept working at its full capacity, and .if the work can be got through in eight hours it is a waste of steam to run it ten hours at less than it is capable of doing. Fifteen minutes spent in adjusting the j valves in the morning may, save two or three hours’ refrigerating at the end of the day, and the fuel bill will be considerably lighter. The old theory that, a machine works best at a certain back pressure, irrespective of the work in hand, dies hard. The back pressure must be regulated to correspond with the temperature of the material to be cooled. For example, a tank of brine at 65° may require a back pressure of 40 lb. to do the best work but if the brine in the tank is at 40°, 15 lb; may be sufficient.

The common mistake is to work the dry-compression machines too hot and the wet-compression too cold. The former results in a too - small flow of ammonia, which takes up all the heat it is capable of absorbing before it has travelled far through the coils, and the heat on the compression side will be very high. In the second case, the flow being too great, the evaporation of the liquid is not completed by the time it gets through the coils. In other words, a portion of the ammonia which has passed through the coils ' has not been made use of. This reduces the capacity of the

machine, and results in the compression side being too cold for the water on the condensers to extract very much heat. Generally speaking, when starting in the morning, it is a good practice to give a machine all the back pressure it will carry, and to gradually close down the valves as the work is got in hand. The sooner a dry-compression machine freezes through to the main return pipe, and the sooner a wet-compression machine freezes back to the expansion-valve, the better. The fact that a return pipe shows frost does not prove, however, that a machine is doing its best work. It shows that the returning ammonia is below freezingpoint, but does not show how many degrees below.

Many of the older cream-vats in use have very little expansioncoil, and cause expense in cooling. It pays to have more coil put in, and at least 9 in. of 1 in. coil to a gallon of cream should be provided.

When the refrigerator was first introduced, into butter-factories the brine-wall was the popular means of cooling insulated rooms. This system has the advantage that it will keep the room down for a time after -the machine has stopped, but it causes dampness. The very shallow drip-tray provided very soon filled up, or was neglected and ran over, and the floor of the room was soon spoiled. A better idea is a wooden tray about 3 in. deep, . and provided with a pipe carried through the cool-room wall to allow the water to flow away as it accumulates.

Coils have largely replaced the brine-tanks of late years, and they are usually hung on the walls with wooden baffles in front to cause a circulation of air. Where the height is available they are sometimes placed in an insulated chamber on top of the coolroom, the air being circulated by means of a fan. The drip-tray is also necessary where coils are used. Coils have the advantage of cooling a room more quickly than a tank, but do not hold it down so well as a brine-tank after the refrigerator is stopped. They give a very much purer atmosphere in a cool-room, and are not so liable to cause dampness. About 9 in. of 1 in. coil to every box of butter is necessary in a cool-room.

The ordinary square 400-gallon tank without insulation .of any kind is still in. use for . chilled water, and is a source of considerable loss during the season. As a .rule it is placed up in the ceiling, where .. all the hottest air in the factory collects. .If iron is used it . must be insulated, but with wooden tanks of 2 in. to 2| in. timber. insulation is not so necessary. A foot of piping to a ,gallon of water is not. too much, to allow, and' a big saving can

be effected if all the ammonia returns are passed through it especially with the dry-compression machines.

FUEL AND STEAM PLANT.

The ever-increasing cost of fuel makes the latter a point requiring attention. Suction gas is coming more into use where the output warrants it, but in small factories it is doubtful whether there is any saving, provided , the boiler is of a good type, well built in, and is properly fired. To make the best use of steam plant, however, the exhaust steam must be ■ used for pasteurizing and heating the water for boiler-feed and washing-up purposes. Some still hold that the boiler-tubes only want cleaning when . they , are dirty “ dirty ” meaning when the soot is z beginning to interfere with keeping up steam. The number of times the tubes require cleaning daily . depends upon the kind of coal used, but they should certainly be done once. Leaking steam-valves run away with a lot of fuel, and with the renewable seated valves of various makes now obtainable there is no excuse.

CHURNING AND MOISTURE-TESTING.

All these losses are small, however, compared with what is possible through neglect in churning. Practically every factorymanager, if asked the moisture-content of his butter, will tell you “ about 15 per cent.,” but very few average that for the year. The moisture test was first introduced as a safeguard against getting over 16 per cent., and by some it is still looked upon in that light only. It is a fact that there are still factories where butter is packed without a test for moisture being made, and I have tested samples which have contained only 13 per cent. . This is a very serious loss to. the factory. On the other hand, to get over 16 per cent, and risk prosecution at the hands of the grader, or, worse still, to have the London buyer prosecuted, is more than any factory can afford. There is only one safe course, and that is to test every churning, and aim at 15 per cent, of moisture. To go over that figure is to risk getting a ' salvy, overworked butter, and frequently exceeding 16 per cent. . • .

There are various methods which can be followed in handling a churn to ensure a fair moisture-content without overworking, and any . remarks made here apply to the open-worker pattern of churn. Whatever method is followed, ■ the buttermaker should be able, with a little experience of his conditions, to bring each churning up to the stage where • the . first test is made with very little variation in

the moisture-content. A churn running at one and a .half revolutions or less per minute on the working-gear will probably have the butter worked sufficiently before 15 per cent, of moisture has been reached, unless the butter is very soft. This is because the churn is travelling too slowly to carry the water up on ■ to . the worker. Two revolutions per minute is a nice working-speed, and I have found the following system of working satisfactory :

After running off the wash-water, put the churn on the slow gear and salt while running. Then throw in the fast • gear and knock the butter together. After putting in the worker, work to the stage where judgment will tell you that it is time to make a moisture test, usually when the butter’ begins to roll over without the rolls breaking and has a tough appearance. How long this will be will depend upon the season of the year, size of the churning, cream-temperature, &c. Now stop the churn, with the drainplug down, and take a sample of butter and test it. If it shows nearly 15 per cent., run off the water which will have collected in the bottom of the churn while the test is being made. ' Then give the churn a few. revolutions to dry off the free moisture, and it will be found that when a final test is made the moisture-content has risen about 0-5 per cent, above the trial test. Should the first test show a low percentage of moisture a little experience of the conditions will show how much more working is needed, and it may also be necessary to make a second test before finishing. A further test taken from the box the following day after the butter has stood twenty-four hours in the cool-room will ensure greater accuracy. '

The value of moisture-testing depends, of course, on whether it is accurately done, and if proper care is not taken it may as well not. be done at all. Considering the amount involved, it is astonishing to see the lack of appliances at some factories, and the rough-and-ready way in which moisture-testing is done. . The scales. must be of the best and a full set of weights kept, and the mug must have no cavities to hold moisture. ' The mug must be thoroughly dry before starting, and should be balanced cold, and also, be allowed to cool before weighing, after roasting off, The difference between a hot and a cold mug will depend .on the mug, and may be up to o-8 . per cent. Reading hot is allowable . for a trial test, but is not accurate enough for fine work.

A loss of i per cent, through deficiency in moisture will cause a difference of 1-45 per cent, in overrun with a butter containing 82 . per cent, of fat. To put it in another way if you have a butter containing 83 per cent, of fat, 14 per cent, of moisture,. and

3 per cent, of salt and curd, your overrun is 19 per cent. By increasing the moisture to 15 per cent, you reduce the fat-content of the butter to 82 per cent., and your overrun will be 20-45. Approximately, a loss or gain of 0-25 per cent, in moisture will make a difference of 0-36 per cent, in overrun.

THE DAILY RECORD.

Keeping a record of the work done daily in the factory has much to recommend it, and if accurately carried out it will often be the means of tracing , any defect. Taking moisture-content as an example, we will assume that 100 boxes of butter have been made during a certain period, and that the average moisture-content is 15 per cent. Allowing 3 per cent, for curd and salt, the butter would contain 82 per cent, of fat. If there was no loss in handling the overrun would be 21-95 per cent. If the overrun is only 20 per cent, the loss in handling must have been about 1-5 per cent, of the total butter-fat . bought. Should this vary to any extent from one period to another, you have then something to go on to locate the leakage. It is the prevention of leakages which makes the difference between good and bad management.

addendum. ■ —- When using exhaust steam for pasteurizing it' is necessary to attach an oil - trap to the steam - pipe leading from the engine to the pasteurizer. Unless this is done the cylinder-oil will adhere to the inner wall of the steam-jacket of the pasteurizer and thus interfere with' the capacity of the machine.

Harrowing Pastures. — Almost the whole of the grass land at Ruakura received a stroke of the chain harrow in May. Where the pasture has been heavily stocked the chain harrow does as much good as a top-dressing. For this work the combined tripod-and - chain harrow cannot be too highly recommended. The chain harrow alone is apt to run over manure which has been lying for some time and become set, and ,the work is therefore not done so effectively. The combined tine-and-chain harrow may be recommended. This is a locally made harrow, and has been in general use on this farm for many years. With the tines turned down this harrow makes a firstclass job on grass land, and when turned over it is one of the most useful implements for harrowing out weeds in the orchard.'—A. W. Green, Manager, Ruakura Farm of Instruction.