![]() ![]() The number of PU's required for a particular beverage depends on several factors, such as the microrganisms it contains and even on the type of packaging. Here is an EXCELLENT summary, (the formula has been simplified to remove the exponents and assumes a constant of 60, but this is good for cider and beer) One pasteurization unit is the microorganism death that occurs in a product held at 60☌ for 1 minute. D For color comparison, the test should be runsimultaneously on an un-pasteurized beer sample.I will post this in the stovetop sticky thread as well, but this way people can get the information without having to read through 126 pages.īasically, you can pasteurize at much lower temps, and as a result, maintain lower pressures, and as a result, suffer fewer bottle bombs, than what is recommended as 'standard' by most of the information on this website regarding stovetop pasteurization.ĭifferent ciders, be they still or sparkling, have different yeast loads and require different amounts of PUs to stabalize them.īut the net-net is that the methods outlined in most of the threads here = are OVERKILL and therefore unnecessarily dangerous at the temperatures they recommend and pressures that result.įirst, we need to understand what a PU is and have a system for measuring them. C If the test tape turns green, the beer has notbeen sufficiently pasteurized. B partially immerse ashort strip of the test tape into the beer, withdraw from the beer and observethe color after 2 minutes. of beerand allow to stand for 30 minutes at room temperature. REAGENTS: A Test tape for glucose - Eli Lilly & Co. The presence ofglucose in beer after sucrose addition indicates the beer has not beensufficiently pasteurized. The presence of glucose canbe detected using glucose oxidase sensitized paper strips. When sucrose is added to a beer containing invertase, thesucrose will be hydrolyzed to fructose and glucose. PRINCIPLE: Beer, which has not been pasteurized, will containactive invertase. The following is a description and procedure for thedetermination of whether beer is pasteurized. Common specification is to aim for <30☌ in the package at exit.īeer can be tested for if it is pasteurised, see enclosed method but the method does not tell us by how much. The exit temperture of the containers has also been shown to be very inportant for quality of the product, if it is too high the flavor can be effected. In extreme cases prolonged pasteurising in the presense of oxygen can lead to darkening of beer color. But the level of these flavors is highly depended on the oxygen content of the beer. Pasteurization flavor has been described as oxidised, bread crust like, cardboard/papery or cooked. Its not possible to give a figure for when beer is scalded. Some brewers only calculate the PU for 60☌ and above but I think more commonly above 50☌ is used. High sugar containing products also need higher PU. level all affect the lethal rate of micro-organism. Minimum PU to achive microbiologically stable beer has been determined to be around 5-6 PU but typically brewers aim for 15-20 PU, with 10 as the minimum.Ĭare must be taken to measure the temperature in the "cold spot" of the container which is normally situated about 2 cm above the bottom. There is approximately ten-fold increase in sterilising effect for every 7☌ increase in temperture.ĭifferent products are pasteurised at different temperature, lager beer is normally pasteurized at 60-62☌, but with low-alcohol beers and malt beverages higher tempertures are used.Typically 64-70☌ The formula is 1,3932 (T-60),, where T is pasteurising temperure. PU unit is defined as one-minute exposure to temperature of 60☌. ![]()
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