This page is designed to be read in conjunction with the cider making guide. The basic processes of cider and perry making are very similar, however the differances are important. References and comparisons will be made to the cider making process throughout this description of perry making. This document is organised into a number of sections. Firstly, the principal stages of the fermentation are described, followed by an overview of the perry making process, a discussion of the characteristics of the pear juice, the microbiology of the process, the changes in the composition of the perry during fermentation, and finally a description of how to make your own perry. Unlike cider making, you do need to know some of the technical detail to make the best possible perry. Research into perry making is less well advanced than into cider making so the depth of detail is not so pronounced. For this reason perry making is more of an art than cider making. There's a further reading section at the end if you want to know more. I'd be more than glad to have your feedback, questions (although I don't promise to be able to answer them all!) and so on. This document is as accurate as I can make it, but you're on your own - I don't accept liability for the contents! the editor
Principles of Fermentation
Perry is made from pear juice which has undergone two different kinds of fermentation. The first fermentation is carried out by yeasts which have either been added deliberately or which are naturally present on the pear skins. This fermentation converts sugars to ethanol and the higher alcohols (fusel alcohols). The second fermentation, the malo-lactic fermentation converts L(-)-malic acid to L(+)-lactic acid and carbon dioxide. This fermentation is carried out by lactic acid bacteria which are present in the pear juice. The malo-lactic fermentation can occur concurrently with the yeast fermentation but more often is delayed until the fully fermented perry reaches 15 C, normally in the late spring or early summer of the year following that in which the perry was made. The Perry Making Process
The process starts with the picking of the pears. These are left to mature for a period of between 2 days and 1 week depending on the variety of pear used. This period is much more critical than the equivalent period for apples in the cider making process. If not left long enough then very little pear flavour is imparted to the perry, if left for too long then the fruit begins to rot from the centre outwards (and thus may go unnoticed) and will ruin the finished perry. The matured pears are crushed in a "scratcher" or in more modern plants they are pulped in a grater mill. As with the cider making process, the crushed pulp is known as the pomace or pommy. Unlike the cider making process, in perry making it is essential that the milled pomace is allowed to stand for a period before pressing. This allows the pomace to lose tannins and thus aids clearing of the perry. The usual period for standing is overnight up to 24 hours. Next the pulp must be crushed to extract the juice. This is done in a cider press, descriptions of which can be found in the cider making guide. The pressed juice is then fermented in one of two different ways. Traditionally the juice is run into wooden pipes (barrels which can contain 120 gallons) or smaller wooden barrels, and the bung is removed. No yeast is added, the fermentation relies on wild yeasts. The fermentation will start within 1-2 days and will continue for several weeks during which time the barrel is topped up with perry. When fermentation is over, the bung is replaced and the perry is matured for 5-6 months. Alternatively the pear juice is treated with sulphur dioxide to inhibit natural wild yeasts, and is then fermented with added pure yeast cultures. The amount of sulphur dioxide which is required is substantially more than is needed for cider making. This is because pear juice contains...
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