The Effect of a Wet and Dry Steep-Out on Barley Respiration and Malt Modification Time. Darwin E. Davidson and Norman O. Jangaard, Research and Development, Adolph Coors Company, Golden, CO 80401. J. Am. Soc. Brew. Chem. 36:0051, 1978.

A comparison of the effect of a wet (slurry) and dry steep-out on barley respiration and malt modification time was made. Barley respiration was determined with the Warburg apparatus. Malt modification was assessed according to ASBC standard methods. The data indicate that a wet steep-out immediately reduces barley respiration by 26%, with a recovery time of up to 28 hr. The time required to reach maximum respiration during germination is also delayed by at least 24 hr. This respiration drop can be caused by either a prolonged submergence time or hydrostatic head pressure. In a production facility, hydrostatic head pressure is probably the dominant factor. Neither root injury nor temperature change during the transfer from steep to germination compartments contributes to the observed respiration "shock". A slower modification rate is associated with the respiration drop caused by the wet transfer.

Keywords: Hydrostatic pressure, Malt, Modification time, Respiration, Steep-out.