the present polyglycerol esters are effective antifoam agents where paper is processed in an aqueous system . typical examples of such processing steps include the following : cooking of paper pulp ; dispensing of pigments in paper - making ; beating of paper stock ; paper - making in a closed circulation system ; paper coating ; and use of recirculation water to carry pulp . the polyglycerol esters have a degree of polymerization of from 3 to 10 , preferably 3 to 6 glycerol units . examples include triglycerols , tetraglycerols , pentaglycerols , hexaglycerols , heptaglycerols , octaglycerols , nonaglycerols and decaglycerols . in addition , these polyglycerol esters have a degree of esterification of from 15 to 85 %, preferably from 30 to 80 %. most desirable are laurate esters having 50 % esterification . the degree of esterification is the number of hydroxyl sites which are esterified divided by the total number of hydroxyl sites multiplied by 100 . the present antifoam agents are derived from c 12 to c 18 fatty acids . the fatty acid may have straight or branched alkyl chains . saturated fatty acids such as lauric , palmitic , stearic , myristic , and isostearic may be used . unsaturated acids which are also suitable include oleic , hexadecenoic acid , and linoleic acid . those derived from lauric acid are especially preferred . the polyglycerol ester antifoam agent is added to the paper processing step in an amount of 1 to 200 ppm , preferably 5 to 30 ppm , based on the recirculating water mass . the present antifoam agent is added to the aqueous paper processing by conventional means at any stage prior to or at the foam generation site . for example , the antifoam agent may be added via a shower in the machine chest , stuff box , saveall or any other accessible area . the various aspects of the present invention will be made more clearly apparent by reference to the following examples . all percentages are on a weight basis unless indicated otherwise . all publications and test methods mentioned herein are incorporated by reference . in the following examples , various polyglycerol esters were tested for their ability to inhibit foam in an aqueous paper processing operation . experiments were performed in a standard dynamic foam test apparatus which recirculates 200 ml synthetic white water for 15 minutes at a temperature of 55 ° c . and a ph of from 7 . 3 to 7 . 5 . the synthetic white water contains rosin , starch , alum , cellulose and calcium carbonate in tap water and simulates recirculation water used in the paper industry . ten ppm of the polyglycerol esters identified in table 1 were injected into samples of the white water . the test procedure consisted of operating the dynamic foam apparatus until an equilibrium foam height was achieved . the time for the foam to reach the initial equilibrium foam height was determined . table 1______________________________________polyglycerol esters as white waterantifoam agents time to reachpolyglycerol % esteri - maximum foamester fication height , seconds______________________________________none ( control ) -- 45decaglyceryl 8 45monolauratehexaglyceryl 13 45monooleatetriglyceryl monolaurate 20 75triglyceryl monooleate 20 60triglyceryl ( 2 . 5 ) 50 180laurate . sup . 1hexaglyceryl 50 150tetralauratehexaglyceryl 50 165tetraoleatedecaglyceryl 50 75hexaoleatetriglyceryl tetralaurate 80 120 . sup . 2triglyceryl tetraoleate 80 60hexaglyceryl ( 6 . 5 ) 81 120laurate . sup . 3decaglyceryl 83 90decalauratedecaglyceryl 83 45decaoleate______________________________________ . sup . 1 indicating an average of 2 . 5 moles of laurate for each mole of triglycerol . sup . 2 average of two runs . sup . 3 indicating an average of 6 . 5 moles of laurate for each mole of hexaglycerol table 1 illustrates the antifoam effectiveness of the present polyglycerol esters . in the absence of the esters , the white water rapidly attained its maximum foam height in 45 seconds . in contrast , when the preferred esters of the present invention were added , as much as a four - fold improvement to 180 seconds was realized ( triglyceryl ( 2 . 5 ) laurate ). over a 2 . 5 - fold improvement ( 120 seconds or longer ) was realized by the use of : hexaglyceryl tetraoleate , triglyceryl ( 2 . 5 ) laurate , triglyceryl tetralaurate , hexaglyceryl tetralaurate , and hexaglyceryl ( 6 . 5 ) laurate . the above examples are intended to be illustrative of the instant invention and should not be construed as limiting the scope thereof . many modifications of the foregoing will be apparent to those skilled in the art which do not depart from the spirit of the invention .