The mixing of seishu after it has undergone kentei (official registration) is called chogo . Even when the raw materials, brewing recipe and other details of the brewing method are the same, there are small variations in the taste and aroma of the finished sake. For most sake, it is necessary to provide stable quality all year round, and blending is used to improve quality, adjust strengths and weaknesses and provide consistency of product.
In some cases, sake of varying characteristics is brewed deliberately and stored in separate tanks blended prior to bottling.
It is possible to predict the chemical make-up of blended sake by calculating from the specifications of the original component sakes, but it is important to carry out sensory evaluation in addition in order to ensure that the blend meets the standards for the product in question.
Compared to whisky and wine, it is rare to find much attention given to blending in the sake world, but it is an important process determining the character of each company’s products.