June 2, 1920.] Agricultural Gazette of N.S.W. 433 



. I . 



systems of pasteurising. The assertion previously made that sodium bi- 

 carbonate is quicker in its action than lime is verified by the results of these 

 investigations under the flash pasteurising system, although after fourteen 

 hours the neutralising force of both had been practically expended ; it was 

 also iiscertained that after the first few hours the additional amount of acidity 

 neutralised by both of ttiese agents was very small. In those cases where 

 the percentage of acidity registered showed an apparent increase contrary to 

 expectation (No. 3, Series B), not only was the mixing of the neutralising 

 agent with the cream inefiicient on account of the structure of the 

 cream vat, but in addition and apart from the presence of carbonic acid 

 gas (COo), it is considered that the overfilling of the vat was a prime 

 cause, as this placed an obstacle or blanket of some 8 to 12 inches of 

 cream above the eoil, thus holding captive the gases seeking to rise to the 

 surface and escape. Whore the quantity of cream put in was just sufficient 

 to reach to the top of the coil or leave it partially exposed, the abnormal 

 condition of the acid registering an increase instead of regularly decreasing 

 did not take place. Leaving the coils slightly exposed is recommended. 

 Care should be taken when adding lime cream or soda (especially the former) 

 to have it well dOuted, and to have it thoroughly and quickly mixed through 

 the mass of the cream that is being treated. It is considered that while 

 good results are obtainable in neutralising by both the flash and holding 

 systems, the former can be credited with obtaining the more consistently 

 good results. The assumption is that it is not the holding system that is at 

 fault but the endeavour to make a Standard coil — used for mixing, heatine. 

 cooling and aerating — fit vats of different shapes and capacities. 



Lime versus Sodium Bi-carbonate. 



Experience has shown that cream neutralised by lime will make butter of 

 a, quality quite equal to that of butter neutralised by sodium bi-carbonate, 

 and the use of lime as a neutraliser cannot, therefore, be condemned. The 

 Department has, however, always cautioned users against the greater danger 

 incurred where lime is added, and, since sodium bi-carbonate has once more 

 come on the market in large quantities and at a reasonable price (a minor 

 consideration), has recommended the use of the latter in preference. There 

 are several reasons for this. Compared with lime, soda is constant in strength 

 and less liable to bring about a change in the butter-fat ; lime, even from one 

 kiln, cannot be relied upon for such consistency. The action of lime is also 

 more enduring than that of soda, and greater care in adding it to the cream 

 and in taking the acidity tests is required. 



In order to assist butter manufacturers to .get more accurate results an 

 arrangement was made with ar firm of manufacturing chemists in Sydney 

 some months ago, whereby the firm agreed to put up a standardised sodium 

 bi-carbonate in cai'tons of various sizes, each package to contain^sufficient to 

 neutralise 1 per cenb: of acidity in 100, 300 or 500 gallons of cream 

 respectively. If the acidity has to be reduced by 3 per cent., three packets 

 of the size required will be necessary. Each of these packets will be plainly 

 labelled to show the weight of soda contained and how much_^acidity it will 



