The internet source for discussion and knowledge on pasteurization equipment, technology, and equipment selection for flash pasteurization, tunnel pasteurization, and used pasteurizers.

Part III - Operating Cost Analysis Packaging - Tunnel Pasteurization Vs. Flash Pasteurization Case Study

Thursday, May 14, 2009


Note; the following article is an excerpt from a (now) more complete article here.

The continued look at flash vs. Tunnel and filtration in terms of operating costs once again shows some eye opening data. If a warmer is needed the energy savings of the flash pasteurizer is not fully realized. The "shocker" in this study is the comparison with filtration. According to this case study the cost of filters was higher than anticipated, indicating that sterile filtration would be the highest of all the options.

If you read the initial post the case study is for a brewery in the Carribean. The view on affluent is that it was (in this case) "free". The students at the brewing academy calculated that the flushing of the filters would send more water to drain than the tunnel, and the warmer would send water to drain even when the packaging line was under continuos running conditions.

The reality is that a cooling tower (to cool and re-use water and avoid effluent) was left out of all three studies but would only serve useful purpose in the tunnel and flash pasateurization scenarios.

Part II - Capital Cost Analysis - Tunnel Pasteurization Vs. Flash Case Study

Sunday, May 3, 2009



For more information on the scenario under which this case study of Tunnel Vs. Flash Pasteurization is investigating, reference last weeks article.

Let's assume the numbers stated above are considered representative. In this scenario, from a capital perspective, Tunnel came out as the winner. Scenarios will change with particular applications, however what can be concluded is that the analysis is more complex (particularly for an existing packaging line) than the cost of a tunnel unit vs. a flash unit. The "equating" of the two (i.e. a tunnel costs $5X and a flash costs $X) is an incomplete outlook.

In the end an operation faced with the decision of Tunnel or Flash would need to consider:
  • Are you cold filling? If so, do you need to bring the product temperature after filling up for packaging? If so, a warmer is required in the operation. This is a significant point in both capital and operating cost. The warmer represents the "non regenerative" (most expensive) portion of the tunnel pasteurizer. The need for a warmer significantly tips the scale on if there will be "savings" on Capital, Operating Costs (including utilities) and Floorspace in the comparison of the two technologies.
  • QA & QC Analysis must be part of the plan. In the Flash scenario we need to ensure and confirm that the filling equipment, containers, and closures will reach and maintain the same state as the pasteurized product arriving to the filler. If the filling operation is not Aseptic (and most are not) there must be a "sanitation" program at the filler in the flash program. This could have different impacts depending on the product and operation, but needs to be in the numbers. In the scenario above a new "aseptic" filler was budgeted.
  • The budget for the flash pasteurizer included a machine which had "Advanced Alarming and Controls", as well as a sterile buffer tank.
  • The cost of installation for a tunnel warmer and a tunnel pasteurizer would not be far off in this case. Assuming the same utility connections, both are single deck and the "scenario" was considering this as a replacement project. In this light the cost of installing either is approximately the same, therefore, the flash unit, sterile buffer tank, and filler all create additional installation costs. If an existing tunnel pasteurizer were to be replaced, it would also require conveyor and controls to close the gap in the line in order that a smaller footprint warmer would fit.
  • A cooling tower was not considered for the warmer scenario, as treated in the assumptions that it already existed for the tunnel pasteurizer. Bear in mind if this were not a machine replacement scenario, this could bring an extra expense into a "flash + warmer" line.

In any study of pasteurization, there must be some confirmation that the process is working to kill undesirable organisms from the product.
  • In the Tunnel Scenario, it was considered to be the machines controls & alarming in conjunction with a "traveller" (passes through the machine and records the temperature profile in the bottle) which is downloadable to aPC in the quality lab.
  • In the flash scenario it was assumed that the flash must have the same level of "sensing redundancy" and "PLC Control" as the tunnel pasteurizer. This indicates that several of the "entry level" / lower cost flash units would not be fail safe for the application.
  • It was also assumed in the flash scenario that the packaging operation must have the ability to "SWAB" and confirm the level of sanitation at the filler and capper.
  • It would also require a "hold" period following which samples could be taken of the finished product and confirmed the process was effective.As stated in a previous article, both processes are effective.
  • Properly applied, the flash will pasteurize the product to perfection. Following that the plant needs to ensure that the systems are in place that the product, containers, and closures are kept in the same state.
The tunnel unit will pasteurize the product and container in the finished state, and is a readily "confirmable" process. It indicates that less QC "maintenance" will be required.

Intro - Case Study for Comparison for Conversion of Existing Packaging Line - Tunnel Pasteurization Vs. Flash Pasteurization

Saturday, May 2, 2009




Note; the following article is an excerpt from a (now) more complete article here.





The following study was done by a group of Students at the Siebel Institute in 2007. Although the data (such as costs) are likely only representative, the findings are interesting:

The scenario is a brewery in the Caribbean contemplating the replacement of a 30 year old tunnel pasteurizer with flash pasteurization or filtration. It is based on a production level of 150 HL/ YR and a product mix which is 95% Light Lagers and 5% Malta. Options are that the existing pasteurizer could be replaced with:

1) Direct Replacement of the existing tunnel pasteurizer
2) Replaced with sterile filtration and filling
3) Flash pasteurization and sterile filling, and warming

The assumptions of the case study were:
No importation taxes onto the Island
· No personnel additions required (Sterile Monitoring/Filter Cleaning)
· This is a 300 BPM packaging line
· Bottles have paper labels, and are packed into plastic crates
· A cooling tower exists which treats pasteurizer discharge water
· Effluent is discharged into the sea at no cost to the brewery
· Capacity exists to treat any effluent additions of the project
· Currently, the brewery \filters lagers to 2ยต, and does not filter Malta
· Cooling is required after the flash to arrive at filling temperatures
· Assumes no QC delay to market, and no impact to WIP
· If a Sterile Filler is purchased, the existing filler can be sold
· Malta would be sent from brew house to 100 bbl BBT
· Cost of spare parts and inventory adjustments has been neglected
· Pasteurizers and Warmers are cleaned by “Boil-Out” which does not create effluent


The assumptions made were:The study requested an analysis of:



  1. Capital Cost
  2. Operating Cost
  3. Shelf Life
  4. QC/QA Practices
  5. Process Changes

These will be the next 5 posts.