Storage of dried grass wafers: Moisture relationships, safe storage periods and changes in durability

Abstract

The behaviour in store of milled and wafered S23 Ryegrass, S48 Timothy and Eynsford Lucerne was studied: A storage trial was carried out at 21°C and 5 r.h. levels from 67–90% on milled and whole dried wafers with and without the addition of a binding agent and/or fungus inhibitor (propionic acid). The addition of propionic acid (33% by weight of 99% solution) had a marked effect, no mould was present at 80% r.h. after 440 days compared with less than 20 days for untreated material. A complementary study established moisture content/r.h. equilibrium relationships. The hysteresis lag between wetting and drying curves was less than 2% at 70% r.h. and curves were similar for three crops studied. Changes in the durability of wafers manufactured with and without the addition of a binding agent, were recorded over a period of 9 months. Where a binding agent was included, wafers were more durable and consistent in manufacture than corresponding untreated wafers. The durability of all wafers declined slightly over the period.