Comparison of Costs of Sterile Cold Filling and Hot Filling of PET Bottles

For the filling of PET bottles for sensitive beverages, there are two safety processes in terms of microbiology, namely heating filling and aseptic cold filling. Both have their own advantages and disadvantages. In addition to considering technology, companies also play an important role in investment decisions.

Products, bottling containers, and bottle caps in aseptic cold filling are individually sterilized and filled under aseptic conditions, without adding preservatives or heat treatment during or after the production process; In the packaging, the product, the bottling vessel, and the bottle cap need to be heated to achieve the sterilization effect. Aseptic cold filling requires a large investment in the equipment, so that its investment costs are higher; and the most expensive part of the PET bottle hot filling is the special bottle for hot filling.

In the cost comparison between the aseptic cold filling and hot filling cost parameters, the two systems are compared. An aseptic cold filling production line and a hot filling production line are required to fill non-steam beverages with a pH below 4.5. For example: juice, ice tea, etc. The starting point is that the capacity of two equipments for filling 0.5-liter bottles is 40,000 bottles/hour, the equipment efficiency is assumed to be 80%, the depreciation period is 6 years, and the interest rate is assumed to be 6%. Energy, chemical supplies and labor costs are calculated at the following prices: electricity 0.07 EUR/kWh; diesel 0.33 EUR/liter; peracetic acid 1.50 EUR/liter; detergents (acid, alkali) 35.00 EUR / Cubic meters; External detergent (foam) 2.00 EUR/kg; Water and waste water 4.50 EUR/m3; Labor costs 3.070 EUR per person per month. Maintenance costs accounted for 3% of investment costs.

Continuous production time comparison Krones's product cost comparison starts from the entire production cycle, cleaning and sterilization are negligible and a batch production of 72 hours is carried out.

This is the experience of Krones and its users. It also includes the conversion of two aseptic cold filling and hot filling products as well as the user's specific downtime, totaling 3.2 hours. Aseptic cold filling also adds about 8 minutes peracetic acid external flush every 4 hours. This results in a net production time of 68.8 hours for each batch of hot fill, compared to 67.9 hours for aseptic cold fill. The average time-to-use aseptic cold filling for the machine replacement molds between cleaning, sterilization, and user batches is 7 hours, which is higher than the average of 6 hours for hot filling. In this way, 72.5 batches of aseptic cold filling are calculated per year, while hot filling amounts to 73.8 batches. Based on the above parameters, 157,502,000 bottles were produced with aseptic cold filling and 162,658,000 bottles were filled with hot water.

The key is that the cost of polyester material is the investment cost per bottle derived from the investment cost and effective production time. For the aseptic cold filling, the total cost per bottle is 20%, compared to the hot filling. Only about 12%. However, this first impression is deceptive. Aseptic cold filling in other aspects such as electricity, heat, maintenance, and consumables and personnel costs accounted for about 13%, while hot filling only 9.4%. Of particular note is that the relative cost of working hours is negligibly small. Although aseptic cold filling requires more labor, personnel spending on three shifts only accounted for 4%, and hot filling was 2.6%.

The decisive factor is also the cost of polyester preforms. For the preforms on the market, there is no additional requirement for aseptic cold filling and the price is calculated at € 40 per 1,000. Heat-resistant bottle preforms for hot filling are 60% higher and the price is calculated at €64 per 1,000. This cost is added to the cost of the two process solutions equal to the cost of caps and labels, which gives the absolute cost of each bottle and its percentage of the total filling cost. The absolute cost of a single bottle for aseptic cold filling is 0.058 euros, which represents 67% of the total filling cost, but the single bottle for hot filling is 0.082 euros. The absolute cost of a single bottle is the proportion of the total filling cost. Up to 79%.

Low-cost, compelling process changes Under the current production conditions, the total cost of single-bottle filling produced by the aseptic cold filling process is 0.0871 euros, while hot filling amounts to 0.1040 euros. Therefore, if all factors are taken into account, the hot filling costs will be 20% higher than the aseptic cold filling of polyester bottles with future prospects. In addition, conventional polyester bottles have almost no restrictions on bottle design and marketing. If the annual filling costs are taken into account and calculated at 157 million times, this difference between the two processes will become even more pronounced. Here, the annual cost of aseptic cold filling can reach 2.6 million euros.