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Best Practices for Cleaning Willmes Presses

Last updated: 6/2021

Applies to: Winemakers with Willmes tank presses, merlin presses, universal presses, progress presses, and sigma presses.

Proper cleaning and care of your Willmes press is an important step to reducing harvest complexities, ensuring you get the most out of your capital investment, and the highest quality end-result for your customers. Here we’ve outlined the necessary steps to properly clean your Willmes press before and after harvest to ensure optimal results.


Destainex-LF (Low Foam)

Clean the interior of your drum and membrane with a 1.0 to 1.5 % solution of Destainex-LF (Low Foam). Destainex-LF is a multi-purpose peroxy-carbonate based cleaner that is used at low levels to effectively remove biofilms, protein, wine color, and mold/mildew from wine contact surfaces. This formulation can be used effectively for automated cleaning systems (one of the recently added options to Willmes Sigma Presses) as well as manually on stainless steel and press membranes.


Destainex-LF Recommended Dosage: 0.5-1.5kg/100L water (0.67-2.0 oz. /gallon)

  • For wine film with no/light color stains: 0.5- 1.0kg/100L water.
  • For wine film with moderate/heavy color stains: 1.0- 1.5kg/100L water.

Always be sure you are using clean, potable water for preparing cleaning solutions.


On presses that have doors that seal, you can simply add the weighed amount of Destainex LF to the appropriate amount of 104°F – 140°F water in the press tank, close the doors, and rotate the press. The cleaning product will have to be mixed separately and manually applied to the surfaces on presses with removable or perforated doors. For these presses add the Destainex-LF to a five-gallon bucket to make a 0.5 to 1.5% solution and then scrub with brushes. Scott Laboratories provides a measuring cup with all Destainex-LF purchases so that you will always add the appropriate concentration to your water.


Willmes Tank Presses

Close all product drains with juice caps or butterfly valves. Add a mixture of 104°F -140°F water and a 0.5 – 1.5 % solution of Destainex-LF to your press. The solution should be enough to cover the bottom of the tank so that all surfaces are in contact with the cleaning solution when the press rotates. Close the doors and rotate the press manually or you can use the Interval Rotation program (if you have this option) to rotate the press and control the duration and the amount of turns if you have this option. Once you have cleaned your press, drain and rinse with clean water to remove all remaining cleaning solution.

Willmes Merlin, Universal Presses (UP) and Progress Presses (PP)

Add the appropriate amount of Destainex-LF and 104°F – 140°F water to a five-gallon bucket and scrub with brushes. Drain and rinse with clean water to remove all remaining cleaning solution.

Willmes Sigma Presses

Close the product valve and add the Destainex-LF solution. The solution must completely cover the bottom of the tank to ensure total contact with the surface of the drum. You can manually turn the press, or you can use the Interval Rotation program (if you have this option) to control the duration and amount of rotations.

The newer Sigma has an option for cleaning the press. Instead of manually rotating the press or using the Interval Rotation, you can use the optional cleaning program. This program adds just enough pressure to the membrane to allow the wrinkles in the in the membrane to relax and disappear. This allows better membrane contact with your cleaning solution. Everything is automatic; all you do is select the amount of time you would like your press to clean. Once you have cleaned your press, drain and rinse with clean water to remove all remaining cleaning solution.


We highly recommend performing this protocol at least once prior to harvest and once after harvest. Beyond that, frequency of cleaning will heavily depend on your harvest size, fruit quality, and down time in between lots. Avoiding proliferation of spoilage organisms in equipment nooks and crannies is critical to maintaining wine quality and avoiding cross-contamination.

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For more tips on preparing your Willmes press for harvest, see this video.