BREWING INDUSTRY RESEARCH FOUNDATION
BEER FROM UNMALTED BARLEY
by J. R. Hudson, Ph.D., F.R.I.C, I. C. MacWilliam, Ph.D., and S. E. Birtwistle, B.Sc.
(Brewing Industry Research Foundation, Nulfield, Surrey)
Received 6th April, 1963
Beers brewed from a grist composed of 25% raw barley and 75% pale ale malt compare favourably with commercial pale ales in flavour, shelf life and head retention.
The substitution of unmalted barley, among other, cereals, for malt in infusion brewing was advocated as long ago as 1883 by Lovibond,3 who observed that barley and rye were superior to rice and maize which were more prone to variable behaviour following variations in grist : liquor ratio, temperature and standing time. Some 60 years later, Baker1—working with laboratory worts obtained from grists containing 50 or 25% of raw barley—noted particularly that the barley needed to be very finely ground to ensure that all the extract was recovered. He made the further point that the amount of nitrogen solubilized was substantially less than is obtained from an all-malt grist under the same laboratory conditions. Baker averred that 6-10% of raw barley could advantageously be used to replace an equivalent amount of malt in conventional infusion brewing. The present communication is to report results obtained when beers were brewed from grists comprising 25% barley flour and 75% conventional pale ale malt on the pilot-plant scale.
Experimental and Discussion
Following the successful brewings with flour from English soft wheat as 26% of the grist,2 a trial was made using a commercial sample of barley flour mixed with three times its weight of a normal kilned malt. This was satisfactorily extracted and converted, and attention was then turned to whole barley which was milled either with a Wiley mill (screen orifice, 0-04-in. diam.) or by successive passages through rolls rotating at different speeds (30:60 r.p.m.), the gap between the rolls being reduced to 0-005 in. for the last passage. Whereas the Wiley mill reduced husk and endosperm indiscriminately to a very fine grist, the roll mill, though grinding the endosperm to a very fine powder, left the husk relatively undamaged and this made for better drainage in conventional brewing.
The barley was mixed with three times its weight of Proctor malt (D.P. 33° L.) prior to mashing at 66° C. (150° F.) using a liquor : grist ratio of 2-4 brl. per Qtr. After standing for 14 hr., sparging was commenced and continued at such a rate that the overall liquor : grist ratio was 6-3 brl. per Qtr. No difficulties were encountered in running off or sparging and extraction was virtually complete, so that the specific gravities of the worts were only about 1° less than is obtained from comparable all-malt brews. This difference is partly accounted for by the moisture content of the barley. The qualities of the worts were normal, except that their nitrogen contents were about 80% of those encountered in all-malt brews. Fermentations were normal and gave beers which were free from foreign flavours, so that in later brews hop rate, colour and dry-hop rate were adjusted to give beers which were analytically similar to pale ales produced commercially.
Typical analyses of worts and beers brewed as described above and of those obtained by using all-malt grists under identical conditions (Table I) showed that, in respect of shelf life and head retention, the beers brewed using barley were rather better than all-malt beers. Moreover, there was a sparing of hop bittering substances which was probably attributable to the relatively low nitrogen content of the worts. Flavour was assessed by comparing the beers with pale ales from commercial sources in numerous ranking tests carried out by tasters with a wide range of experience. In all such tests, the beers were found to lie within the commercial range.
It may be noted that the reduction (16-20%) in nitrogen solubilized at mashing is not as great as reported by Baker (~50%), which is doubtless due in part to the effect of using, in the brewery, mashes which are thicker than those produced by the standard laboratory method (cf.4).
Acknowledgement.—The encouragement and advice given by Dr. A. H. Cook, F.R.S., in the course of this work are gratefully acknowledged.
1. Baker, J. L., this Journal, 1842, 109.
2. Birtwistle, S. E., Hudson, J. R. & MacWilliam, I. C, this Journal. 1962, 467.
3. Lovibond, T. W.. Brewing with Raw Grain. London: E. & F. N. Spon, 1883.
4. MacWilliam, I. C, Hudson, J. R.. & Whitear, A. L., this Journal. 1963, 303.