diff --git a/assets/src/bundles/vault/vault-create-tasks.js b/assets/src/bundles/vault/vault-create-tasks.js
--- a/assets/src/bundles/vault/vault-create-tasks.js
+++ b/assets/src/bundles/vault/vault-create-tasks.js
@@ -71,7 +71,7 @@
       cookingUrl = Urls.api_1_vault_cook_git_bare(cookingTask.swhid);
     }
     if (cookingTask.email) {
-      cookingUrl += '?email=' + cookingTask.email;
+      cookingUrl += '?email=' + encodeURIComponent(cookingTask.email);
     }
 
     try {
diff --git a/cypress/integration/vault.spec.js b/cypress/integration/vault.spec.js
--- a/cypress/integration/vault.spec.js
+++ b/cypress/integration/vault.spec.js
@@ -407,6 +407,45 @@
         .should('contain', 'Archive cooking request successfully submitted.');
   });
 
+  it('should create a directory cooking task with an email address', function() {
+
+    // Browse a directory
+    cy.visit(this.directoryUrl);
+
+    // Stub responses when checking vault task status
+    const checkVaulResponses = [
+      {'exception': 'NotFoundExc'},
+      this.genVaultDirCookingResponse('new'),
+      this.genVaultDirCookingResponse('pending', 'Processing...'),
+      this.genVaultDirCookingResponse('done')
+    ];
+
+    // trick to override the response of an intercepted request
+    // https://github.com/cypress-io/cypress/issues/9302
+    cy.intercept('GET', this.vaultDirectoryUrl, req => req.reply(checkVaulResponses.shift()))
+      .as('checkVaultCookingTask');
+
+    // Stub responses when requesting the vault API to simulate
+    // a task has been created
+    cy.intercept('POST', this.vaultDirectoryUrl + '?email=foo%2Bbar@example.org', {
+      body: this.genVaultDirCookingResponse('new')
+    }).as('createVaultCookingTask');
+
+    cy.contains('button', 'Download')
+      .click();
+
+    cy.window().then(win => {
+      // Create a vault cooking task through the GUI
+      cy.get('.modal-dialog #swh-vault-revision-email')
+        .type('foo+bar@example.org', {force: true});
+      cy.get('.modal-dialog')
+        .contains('button:visible', 'Ok')
+        .click();
+
+      cy.wait('@createVaultCookingTask');
+    });
+  });
+
   it('should offer to recook an archive if no longer available for download', function() {
 
     updateVaultItemList(this.vaultItems);