A process of making a water-soluble detergent unit dose article comprising the steps of: (a) providing a water-soluble non-woven fibrous sheet on a roll; (b) unwinding the water-soluble non-woven fibrous sheet in a machine direction from the roll via at least a first intermediate roll; (c) feeding the water-soluble non-woven fibrous sheet from the at least one intermediate roll via a forming unit to shape the water-soluble non-woven fibrous sheet into a tube shape; (d) sealing the water-soluble non-woven fibrous sheet via a machine direction seal, a cross-direction seal or a mixture thereof to create a container having an open end; (e) filling the open container with a water-soluble granular detergent composition; (f) sealing the second open end via a machine direction seal, a cross-direction seal or a mixture thereof to form a water-soluble unit dose article; wherein the forming unit comprises a hollow forming tube, wherein the hollow forming tube comprises at least two passages, a first passage and a second passage, wherein the first passage runs along the length of the forming tube from the top of the forming tube to the bottom of the forming tube, wherein the second passage runs parallel to the first passage and extends from the top of the forming tube to at least two thirds down the length of the forming tube, wherein the second passage is connected to the first passage by at least two air vents, a first air vent that connects the first passage to the second passage in a position within the top half of the forming tube, and a second air vent that connects the first passage to the second passage in a position within the bottom half of the forming tube, such that the second passage forms an air duct from the first passage to the volume space above the forming tube, wherein during step (e) the open container is filled by passing the water-soluble granular detergent composition through the first passage, but not the second passage, of the forming tube such that the water-soluble granular detergent composition travels from the top of the forming tube to the bottom of the forming tube and into the open container, and wherein during step (e) any displaced air that is caused by the passage of the water-soluble granular detergent composition through the first passage, can move through the first air vent and/or second vent from the first passage to the volume space above the forming tube via the second passage. (a) providing a water-soluble non-woven fibrous sheet on a roll; (b) unwinding the water-soluble non-woven fibrous sheet in a machine direction from the roll via at least a first intermediate roll; (c) feeding the water-soluble non-woven fibrous sheet from the at least one intermediate roll via a forming unit to shape the water-soluble non-woven fibrous sheet into a tube shape; (d) sealing the water-soluble non-woven fibrous sheet via a machine direction seal, a cross-direction seal or a mixture thereof to create a container having an open end; (e) filling the open container with a water-soluble granular detergent composition; (f) sealing the second open end via a machine direction seal, a cross-direction seal or a mixture thereof to form a water-soluble unit dose article; wherein the forming unit comprises a hollow forming tube, wherein the hollow forming tube comprises at least two passages, a first passage and a second passage, wherein the first passage runs along the length of the forming tube from the top of the forming tube to the bottom of the forming tube, wherein the second passage runs parallel to the first passage and extends from the top of the forming tube to at least two thirds down the length of the forming tube, wherein the second passage is connected to the first passage by at least two air vents, a first air vent that connects the first passage to the second passage in a position within the top half of the forming tube, and a second air vent that connects the first passage to the second passage in a position within the bottom half of the forming tube, such that the second passage forms an air duct from the first passage to the volume space above the forming tube, wherein during step (e) the open container is filled by passing the water-soluble granular detergent composition through the first passage, but not the second passage, of the forming tube such that the water-soluble granular detergent composition travels from the top of the forming tube to the bottom of the forming tube and into the open container, and wherein during step (e) any displaced air that is caused by the passage of the water-soluble granular detergent composition through the first passage, can move through the first air vent and/or second vent from the first passage to the volume space above the forming tube via the second passage.