Author Topic: Sterilizing / Rinsing lines pre and post wort transfer  (Read 6706 times)

Offline YanezInc

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Sterilizing / Rinsing lines pre and post wort transfer
« on: July 17, 2015, 02:01:17 AM »
Hi there people... I just joined the forum as of today. My name is Manuel and I am studying to become a master brewer... I am currently carrying (or trying to at least) an efficiency optimization project at a medium sized brewery. My question here is regarding food grade sterilization or rinsing practices of hoses and pipe lines. In two different breweries besides the one at hand, I have come across the case in which they use hot water (@ hot water tank SP temperature) to "sterilize" hoses and lines pre and post wort transfer from the boiling kettle to the fermentation tank. I wouldn't go as far as to call it "sterilization" because there is no real calculation in any of the cases that I have been given supporting these practices but that is, I now realize, quite a common practice I assume in craft and medium sized breweries at least.

What I am trying to challenge here is the amount of water and residence time so as to be able to generate some savings from hot water use in rinsing... I wanted to have some sort of sterilization or pasteurization calculation background to justify the amount of hot water used and temperature as well, but have not come across anything yet.

SO... in conclusion... can any of you point into some direction / literature where I might find something or have you by yourselves done some calculations so as to determine the optimal amount of boiling/hot water to use?

Offline brewfun

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Re: Sterilizing / Rinsing lines pre and post wort transfer
« Reply #1 on: July 17, 2015, 07:35:37 AM »
Hi there people... I just joined the forum as of today. My name is Manuel and I am studying to become a master brewer...

Very cool! Congrats!
Quote
My question here is regarding food grade sterilization or rinsing practices of hoses and pipe lines. In two different breweries besides the one at hand, I have come across the case in which they use hot water (@ hot water tank SP temperature) to "sterilize" hoses and lines pre and post wort transfer from the boiling kettle to the fermentation tank. I wouldn't go as far as to call it "sterilization" because there is no real calculation in any of the cases that I have been given supporting these practices but that is, I now realize, quite a common practice I assume in craft and medium sized breweries at least.

If you haven't studied it yet, Pasteurization is one of the most common forms of sterilization available for food and equipment. It's a very common way to sanitize Heat Exchangers (Hx), lines, hoses, filters, semi-porous surfaces and even product.

Quote
What I am trying to challenge here is the amount of water and residence time so as to be able to generate some savings from hot water use in rinsing... I wanted to have some sort of sterilization or pasteurization calculation background to justify the amount of hot water used and temperature as well, but have not come across anything yet.

SO... in conclusion... can any of you point into some direction / literature where I might find something or have you by yourselves done some calculations so as to determine the optimal amount of boiling/hot water to use?

The amount of water is whatever it takes to have the shortest rise time, Residency is based on temperature and of course, temperature is determined by process and product contact. You wouldn't heat beer past the minimum temperature needed to meet your sanitation and shelf life specs.

I pasted a table below from the FDA website. Hopefully it isn't a mess when I post. For the process you described, use a loop back to the HLT to conserve water, plus a bypass to discharge and early running that are flushing product.

Most breweries aim for 80C at the far end of the run, simply because it's a round number. At that point, the water needs less than 15 seconds of contact time. Breweries tend to leave the Hx and lines packed with the hot water. If the time or distance will cause a vacuum, using the O2 stone to re-pressurize is also common. Pure O2 is a sterilant, too.

Temperature         Time                       Pasteurization Type
63┬║C (145┬║F)1)   30 minutes                      Vat Pasteurization
72┬║C (161┬║F)1)   15 seconds      High temperature short time Pasteurization (HTST)
89┬║C (191┬║F)   1.0 second           Higher-Heat Shorter Time (HHST)
90┬║C (194┬║F)   0.5 seconds   Higher-Heat Shorter Time (HHST)
94┬║C (201┬║F)   0.1 seconds   Higher-Heat Shorter Time (HHST)
96┬║C (204┬║F)   0.05 seconds   Higher-Heat Shorter Time (HHST)
100┬║C (212┬║F)   0.01 seconds   Higher-Heat Shorter Time (HHST)

If cold sanitation is desired, the use of Ozonated water in the form of Periacetic acid at 2% is the most common pre fermentation method. Post Fermentation, Pasteurization is still used, but typically from an isolated hot water source instead of the HLT. Cold water sanitizers are dioxi chlor, iodaphor or sanistar. Periacetic acid can be used post fermentation, but it needs about 10 minutes of time to gas out, or the ozone will harm the beer flavor.
Beer Appreciation is the space between pints.

Offline YanezInc

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Re: Sterilizing / Rinsing lines pre and post wort transfer
« Reply #2 on: July 20, 2015, 03:07:07 AM »
Hi there brewfun,

First of all thanks for taking the time to reply! I probably did not explain myself correctly... I am familiar with pasteurization theory regarding beer, but as you said have not really gone over pasteurization or sterilization for different materials such as hoses (food grade), pipes (different types of steel), tanks and the like.

My thought here was regarding different material porosity and roughness. I know that porous surfaces can be seats of infection and as such wanted to be extra careful, however I am not sure how much of an impact surface roughness or porosity can have over sterilization/pasteurization effectivity and if pasteurization time can thus be compensated for by some sort of deviation factor that takes porosity into consideration.

Thanks again! I will have a look at the FDA website and see if I can find any suggestions for food grade hoses and pipes. If you remember anything else that might be of help please do share it.

cheers!

Offline pcollins

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Re: Sterilizing / Rinsing lines pre and post wort transfer
« Reply #3 on: July 20, 2015, 03:29:57 AM »
If I understand correctly you're talking about sanitizing lines prior to transfers or cooling in?

We're using 180┬║F water for contact time of 15 minutes. The amount of water "used" is only the amount lost in the lines post-sanitizing and at the time of cooling in. The water is recirculated into the HLT so there is a minimum of loss in the process. Amount lost varies on line length in the set up. Depending on the location of the fermenter we're using we have to use a different length of line to reach it.

As far as the sanitizing of porous surfaces during that time it's not just about the contact time with the water, the water is also heating up parts that don't come in direct contact. Our aeration/oxygenation stone is in place during line circulation. Whether 100% of the surfaces of that come in contact with the water is not absolutely relevant as the entire unit is going to be heated up to 180┬║ in the process.

Maybe also do some searches on probrewer to see what has been mentioned there.


Offline brewfun

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Re: Sterilizing / Rinsing lines pre and post wort transfer
« Reply #4 on: July 29, 2015, 08:21:31 PM »
As far as the sanitizing of porous surfaces during that time it's not just about the contact time with the water, the water is also heating up parts that don't come in direct contact. Our aeration/oxygenation stone is in place during line circulation. Whether 100% of the surfaces of that come in contact with the water is not absolutely relevant as the entire unit is going to be heated up to 180┬║ in the process.

Right.

The critical temperature is 161o F (72o C). At that temperature, Pasteurization is achieved in 15 seconds. Longer residency is fine and this temp is lower than the distortion temperature of some plastic parts used in brewing, like Noryl plates on filters as well as being safe for DE leafs.
Beer Appreciation is the space between pints.