Pasteurization Unit

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Pasteurization Unit

Postby BizKettle » Mon Jul 21, 2008 5:27 am

Hallo everyone!

I should have a pasteurization of my beers. But is quite difficult to decide how. I have thought to use a hot water bath where keep the bottles for a period of time determined, checking the temperature inside by a thermometer, according to the time.
So now I have a question:
1)How could I calculate the united of pasteurization, when i have the data time and temperature? As I know, temperature inside the bottle start to raise and tend to be equal to hot water. For raising and decreasing, how should I use the data to have the PU? Do Somebody know some software that could help me?

Thank you very much for your help. I remain very truly yours.

Andrew
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Re Pasteurization

Postby billvelek » Mon Jul 21, 2008 8:54 am

I don't really know how you could do that, but I do want to ask you WHY you want to do it.

Pasteurization is used for preservation and is generally unnecessary for health reasons with beer (there are NO know pathogens which can survive in beer), and I would imagine it would even be detrimental to homebrews. The reason I said detrimental is that I'm speculating that the dead yeast, which would otherwise survive for perhaps months, will immediately begin to decay, spilling their guts out and affecting the flavor of your beer in a negative way; that is called "autolysis". Commercial beer probably doesn't need to deal with that problem because I would imagine that any company which pasteurizes probably also filters their beer first to remove the yeast, thus no autolysis problem. Commercial brewers are probably also trying to maximize shelve storage life. Homebrewers, on the other hand, are usually more concerned with quality without TOO much trouble, and going through filtering and/or pasteurization (which then requires artificial carbonation because there is no yeast available to do it), seems like a lot of trouble for nothing.

Now, the bottles also add another potential problem, although I'm not sure how significant it is; the beer must be fully carbonated before you pasteurize the bottles because it if it isn't then how do you think you will get it carbonated? You mention measuring the temperature inside the bottles, which implies that the bottles are somehow opened; if the beer is carbonated and the bottles are opened, they will foam up and you will lose beer and carbonation. If they remain sealed, you can only calculate the internal temperature rather than measure it, and you might be risking some bottle bombs; regarding the latter, you do realize that you will be increasing the pressure inside the sealed bottles as you raise the temp, right?

Now, if you really want to pasteurize your beer, let me suggest that you would follow these steps in this order:
1. Filter the yeast out of your beer;
2. Pasteurize before carbonation, such as by kegging it and then warming the keg up to pasteurization temp and then cooling it back down;
3. Artificially carbonate inside the pasteurized keg.

Now, if you want the beer in bottles, you would ordinarily use a counter-pressure filler to transfer carbonated beer from the keg to your bottles, but in the process your beer will be exposed to airborne microbes, which will presumably defeat the purpose of pasteurization unless you go to some ridiculous lengths to compenate for that.

Just my two cents.

Bill Velek
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Postby BizKettle » Mon Jul 21, 2008 9:33 am

Hi Bill

Thank you for your reply. Now I will search to explain what maybe I have not do up your reply. I have intention to have a temperature measurement in one single open bottle. So others will be closed. Second I think that bottling with very cold beer could avoid the carbonation problem of the final product.
Third, I have considered pressure inside the bottle. At 70 °C inside the bottle should be about 9 bar. In theory, my bottles should be quite resistant. I hope !!! I tell you if don't!
About yeast, yes you write right, this is a real problem. I have a 5 um filter and I hope to obtain a yeast number so low to don't have off flavour problem caused by yeast autolysis. But this remain the critical point...

I am only curious, I would like check what pasteurization could do and how.

So my the problem is...how could calculate The unit pasteurization? I know there is a formula, but is quite difficult to apply it in a real problem. I have just reported the reason. Somebody could help me? (should be a mathematical problem)

Thank you very much

Andrew
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More about pasteurization

Postby billvelek » Mon Jul 21, 2008 10:06 am

Unfortunately, this group here is not particularly active, and on top of that, I don't think very many homebrewers pasteurize, so you might not find an answer here or it might take a long time; on the other hand, we do have several very intelligent and educated brewers here, so maybe you will get better help than I can provide. Meanwhile, I suggest that you might want to consider posting your query in some of the more active homebrewing forums, such as http://www.brewboard.com, Usernet Group rec.crafts.brewing, some of the Yahoo brewing groups (there are many, and http://groups.yahoo.com/group/home_brew is one of the largest), and to the Homebrew Digest -- http://hbd.org

As for what I can suggest to directly answer your question, I think your suggestion of leaving one bottle open and checking its temp is probably the best, and perhaps only, practical solution. I have a 5-gallon pot that is 12" in diameter, and I can fit 18 12-oz. bottles in it at one time, so three sets will handle a 5 gallon batch. I don't know anything about 'units of pasteurization', but I have googled the subject and found that milk is heated to 71.7 °C (161 °F) for 15-20 seconds. I don't know about beer. Considering the trouble you're already going to, I'd probably bump it up to a little higher temp for a little longer, since beer doesn't have the problems that milk has when heated. I say that because you might have an issue with an even distribution of heat, meaning that your sample bottle might indicate 71C but other bottles might not be that high yet. I think that a slow heat to maybe 80C in your test bottle would most likely cover all of your other bottles to a high enough temperature.

I can understand how you might want to experiment with this; I try different things myself. However, since you already filter your beer, my prediction is that you will probably not detect any noticeable difference in your beer that would ever justify the effort, but sometimes we need to learn from our own experiences. If you see any improvement, please post your results.

Good luck.

Bill Velek
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Postby BizKettle » Mon Jul 21, 2008 10:32 am

Thank you very much Bill. I am glad to have known you. If I have good news, i will post them.
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Postby beernut » Thu Nov 27, 2008 10:42 pm

I believe commercial breweries pasteurize their beer to maintain a set taste standard so it won't be influenced by any inadvertent outside parameters.
Meaning if you open a bottle today of X brew it will taste much the same as X brew you opened six monthes ago of a different batch with little or no varience
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