Good beer is characterized by a few quality traits, which are easy to agree upon. They are: 

(i) flavour (combination of taste, aroma and mouthfeel); 

(ii) appearance (colour, clarity, foam, and beading); 

(iii) wholesomeness (absence of hazardous compounds, presence of useful compounds). 

Given the choice (which isn't always the case) brewers throughout the world prefer good quality malt. They believe that this will increase their chances of both professional and commercial success. Significantly, they know that with the right malt, the job of making good beer will be easier. But, despite (or perhaps because of) a voluminous literature on the topic, they encounter more difficulty in defining good malt than they do in defining good beer. It is my purpose in this paper to address this issue. 

Barley malt grains are partially-germinated seeds which have been heated and dried. Contrary to expectation, they are not necessarily dead. Many can re-germinate, given the opportunity (water, air, time), though they are seldom capable of forming a healthy plant. 

Malts fall into two broad types: standard malts and speciality malts. Standard malts, which include those used for the bulk of the grist of both lagers and ales, provide extract, flavour, colour, and nutrients for yeast. Speciality malts are used primarily to supply colour and flavour, while sacrificing extract yield. 

One very important aspect of malt is that it is substantially inhomogeneous. There are considerable differences between individual corns. This has a major impact on processing, and on prediction of the performance of a single batch. It is all too easy after looking at an analysis sheet of a single batch of malt to make the mistake of thinking that we are dealing with a homogenous product. This is never so.