A Startup’s Guide to Batch and Tunnel Pasteurization and Contract Processing 

Presented by PRO Engineering / Manufacturing Inc., a leading U.S. maker of tunnel and batch pasteurization systems for the global beverage industry. With decades of experience building energy-efficient, precision-controlled pasteurizers, PRO helps brands scale safely while keeping flavor, quality, and functional integrity intact. 

Summary:  Startups usually choose batch pasteurization of sealed packages, continuous tunnel pasteurization after filling, heating the liquid before filling (like flash pasteurization, typically from other builders), or a qualified co-packer.  
 
Formulation, package, volume and shelf-life goals decide the fit. PRO builds batch and tunnel pasteurizers for sealed packages. 

Table of Contents 

  1. Introduction 
  1. Batch vs. Tunnel Pasteurization
  1. Sealed-Package vs. Before-Filling Treatment
  1. What Startup Pasteurization Really Costs 
  1. Formulation, Packaging, and Your Process 
  1. PRO Equipment for Startups 
  1. Questions for Any Manufacturer 
  1. Market Growth and Industry Data 
  1. Equipment Comparison 
  1. What PRO Customers Say 
  1. Frequently Asked Questions 
  1. Conclusion 
  1. About the Author 

Introduction

Pasteurization shapes a young brand’s cash flow, consistency, staffing and realistic growth. Start with three questions: What are you treating? When? And how much do you need to run? 

Batch vs. Tunnel Pasteurization

A batch pasteurizer is a chamber. Load sealed bottles or cans, run a heat-hold-cool cycle, unload. PRO’s batch units spray heated water onto packages rather than submerging them. 

A tunnel moves sealed packages continuously through heating and cooling zones and ties straight into your filling line. 

Batch is compact and suits small runs, frequent product changes and recipe development, but labor per case climbs with volume. Tunnels need more floor space and maintenance while cutting manual handling. There’s no universal switch point. Your scheduling, labor and distribution reality decide. 

Sealed-Package vs. Before-Filling Treatment

Treating sealed packages heats the drink, container interior and closure together. That protects against contamination during filling, but packages must tolerate heat and pressure. 

Flash pasteurization heats flowing liquid in a heat exchanger before filling, so filling, package and closure controls must also be suitable and validated. PRO focuses on sealed packages; pre-fill systems come from other builders. 

And these aren’t interchangeable: a cooling tunnel cools but doesn’t pasteurize, immersion systems submerge sealed packages in a heated bath, and spray systems apply heated water through nozzles. See this survey of microbial presence and growth in beverage-industry tunnel pasteurizers. 

What Startup Pasteurization Really Costs

Image of beverages in a glass for a new article by PRO Engineering / Manufacturing Inc.

Beyond the machine price, budget for installation and conveyance, facility prep and utilities, labor and handling, monitoring and documentation, testing and validation, cleaning, maintenance and parts, plus training and room to expand. 

PRO’s Single-Temp batch pasteurizer page describes a trade-up program crediting a batch unit toward a tunnel, plus financing. Confirm terms with PRO. 

Price a qualified co-packer too. It lets you validate your product and prove demand while someone else carries the equipment overhead. 

Formulation, Packaging, and Your Process

Formulation factors include pH, residual sugar (the refermentation risk in cider, kombucha and sweetened ready-to-drink cocktails), carbonation (which builds pressure in a heated sealed package), alcohol and heat-sensitive ingredients like hop aroma. Packaging factors include container dimensions, material, closure integrity, storage conditions and target shelf life. Beer, cider and suitable nonalcoholic drinks are long-established tunnel applications. 

Conventional pasteurization doesn’t automatically make a low-acid beverage shelf-stable. Have a qualified process authority review your formulation, package, storage and applicable rules before choosing equipment, including the low-acid food rules in 21 CFR Part 113 on the eCFR and the FDA’s Juice HACCP questions and answers for juice products. Don’t assume plastic can run at conditions validated for cans or glass. 

Plainly put: equipment alone doesn’t establish safety or shelf stability. Formulation, package and process all need validation. 

PRO Equipment for Startups

  • Triple-Temp Batch Pasteurizers: three temperature profiles simulating tunnel cycles. PRO’s example cites 12 pasteurization units, also conditional. 

The PM-4 Pasteurization Monitor rides through a tunnel with a sample container. One probe tracks the product’s cold spot, another spray water. It records both plus elapsed time and calculates pasteurization units (PUs), the standard measure of accumulated heat treatment. Water and product temperatures differ, and the cold spot governs the process. 

Questions for Any Manufacturer

  1. Does my product and packaging combination suit it? 
  1. What throughput fits my application, not the brochure? 
  1. What utilities, footprint and installation are needed? 
  1. What monitoring and records does it produce? 
  1. What cleaning access, training, service and parts support exist? 
  1. Can it expand or integrate with my filling line? 
  1. Who owns validation: you, me or a process authority? 

Market Growth and Industry Data

For scale, the Brewers Association’s 2024 U.S. craft brewing industry figures show craft brewers produced 23.1 million barrels in 2024, down 3.9% from 2023. Craft retail dollar value rose 3% to an estimated $28.8 billion, or 24.7% of total U.S. beer retail dollar sales. That’s history for one segment, not a forecast. 

Equipment Comparison

  • Carbonated beer (cans or glass; plastic not assumed), launch or local: Single-Temp or Triple-Temp Batch. Validate PU target and shelf life. 
  • Cider, kombucha, RTD cocktails (refermentation risk), small multi-product runs: Triple-Temp Batch. Validate sugar/yeast risk; monitor PUs. 
  • Growing brand entering regional retail, mid-volume continuous: SlimLine Tunnel. Verify PU delivery at line speed. 
  • High-volume automated lines: PRO/Line Large Tunnel, with scheduled process, records and maintenance. 
  • Low-acid shelf-stable nonalcoholic drinks in hermetically sealed containers, any scale: process-authority assessment first for 21 CFR Part 113 classification and scheduled process. 

What PRO Customers Say

“We contracted PRO Engineering/Manufacturing to meet our pasteurizing needs. During our expansion we had a lot of equipment being installed and commissioned. 
 

PRO Engineering did a great job keeping us updated during the build process of our new Slim/Line Tunnel Pasteurizer. Our pasteurizer arrived on time and was securely shipped.  
 
Even with the Covid-19 pandemic Andrzej Michalski, our Sales Rep, was able to check in on our installation. PRO Engineering did a great job making the equipment plug and play for an easy install.”  
Matt Pochmara – Warehouse & Packaging Manager ⭐⭐⭐⭐⭐ 

Frequently Asked Questions

Does every drink brand need pasteurization? No. It depends on formulation, pH, alcohol, packaging and distribution. Pasteurization is a mild heat treatment that reduces microorganisms and enzymes, applied before or after packaging. Reference: Wikipedia’s overview of pasteurization. 

Is tunnel pasteurization better than batch? Neither always wins. Batch suits small runs, frequent changes and limited capital; tunnels suit continuous, line-integrated production. Reference: PRO’s SlimLine tunnel pasteurizers. 

Can PET or plastic bottles be pasteurized like cans or glass? Not automatically. Container type, size and material affect what heating and cooling a package tolerates. Reference: Kunz et al. tunnel pasteurizer survey. 

What is a pasteurization unit (PU)? In brewing, one PU equals one minute at 60°C (140°F). Reference: MBAA Food Safety Bite on pasteurization. 

Does pasteurization guarantee shelf life or safety? No. A process authority should classify low-acid products, and juice needs Juice HACCP assessment. References: FDA Juice HACCP guidance and 21 CFR Part 113. 

Should a startup use a co-packer before buying equipment? Possibly. It lets you test demand before committing capital. Reference: PRO’s guide to pasteurization systems for beverage co-packers. 

Conclusion 

Before requesting a quote, gather formulation details (pH, residual sugar, alcohol), package sizes and materials, per-shift targets, facility limits (footprint, utilities) and processing requirements (target PUs, validation status). Share them through PRO’s contact page. Next, read PRO’s guide to choosing the right tunnel pasteurizer size. 

About PRO Engineering / Manufacturing Inc. 

PRO Engineering & Manufacturing Inc. has been helping beverage producers scale with confidence since 1977. From batch pasteurizers and SlimLine tunnel systems to full-scale continuous processing lines and advanced monitoring technologies, PRO delivers customized thermal processing solutions for manufacturers at every stage of growth.   

Ed Michalski is CEO of PRO Engineering / Manufacturing Inc., which Ed and Dave Michalski founded in 1977 as a steel fabrication shop. The company builds, sells, and services tunnel and batch pasteurizers plus beverage warming, cooling, and conveying equipment. 
 
Built on decades of hands-on engineering expertise, PRO’s systems are designed to improve quality, efficiency, and long-term profitability.  
 
📞 (414) 362-1500 | ✉️ sales@prowm.com/| 🌐 prowm.com | 11175 W. Heather Avenue, Milwaukee, WI 53224 USA (Map) 

References 

  1. Brewers Association, 2024 U.S. Craft Brewing Industry Figures (released April 15, 2025; updated May 6, 2025). Accessed October 28, 2026. 
  1. Wikipedia, Pasteurization. Accessed October 28, 2026. 
  1. eCFR, 21 CFR Part 113: Thermally Processed Low-Acid Foods Packaged in Hermetically Sealed Containers. Accessed October 28, 2026. 
  1. FDA, Guidance for Industry: Questions and Answers on the Juice HACCP Regulation. Accessed October 28, 2026. 
  1. Kunz, O., et al., A Survey of the Microbial Presence and Growth in Tunnel Pasteurizers of the Beverage Industry, Journal of Food Processing and Preservation (2026). Accessed October 28, 2026. 
  1. Master Brewers Association of the Americas, Food Safety Bite: Pasteurization (September 2024). Accessed October 28, 2026.