diff --git a/guix/ui.scm b/guix/ui.scm
index 5ae082fc0a..3a0a6501d1 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -635,16 +635,17 @@ report what is prerequisites are available for download."
 (define (right-arrow port)
   "Return either a string containing the 'RIGHT ARROW' character, or an ASCII
 replacement if PORT is not Unicode-capable."
-  (with-fluids ((%default-port-encoding (port-encoding port)))
-    (let ((arrow "→"))
-      (catch 'encoding-error
-        (lambda ()
-          (call-with-output-string
-            (lambda (port)
-              (set-port-conversion-strategy! port 'error)
-              (display arrow port))))
-        (lambda (key . args)
-          "->")))))
+  (let ((encoding (port-encoding port))
+        (arrow "→"))
+    (catch 'encoding-error
+      (lambda ()
+        (call-with-output-string
+          (lambda (port)
+            (set-port-encoding! port encoding)
+            (set-port-conversion-strategy! port 'error)
+            (display arrow port))))
+      (lambda (key . args)
+        "->"))))
 
 (define* (show-manifest-transaction store manifest transaction
                                     #:key dry-run?)
diff --git a/tests/ui.scm b/tests/ui.scm
index 058207e8b9..cfe417d497 100644
--- a/tests/ui.scm
+++ b/tests/ui.scm
@@ -248,9 +248,12 @@ Second line" 24))
                             (lambda ()
                               (show-manifest-transaction store m t)))))
            (string-match "guile\t1.8.8 -> 2.0.9"
-                         (with-fluids ((%default-port-encoding "ISO-8859-1"))
-                           (with-error-to-string
-                            (lambda ()
-                              (show-manifest-transaction store m t)))))))))
+                         (with-error-to-string
+                           (lambda ()
+                             ;; In Guile 2.2, %DEFAULT-PORT-ENCODING doesn't
+                             ;; influence the encoding of string ports.
+                             (set-port-encoding! (current-error-port)
+                                                 "ISO-8859-1")
+                             (show-manifest-transaction store m t))))))))
 
 (test-end "ui")