diff --git a/stories/src/helpers.tsx b/stories/src/helpers.tsx
index 7b3caf1c..f62703d1 100644
--- a/stories/src/helpers.tsx
+++ b/stories/src/helpers.tsx
@@ -98,6 +98,9 @@ export const xKnob = (table: Table, initial?: string) =>
 export const yKnob = (table: Table, initial?: string) =>
   select('y', findXYColumns(table), initial || '_value' || 'cpu')
 
+export const yKnobString = (table: Table, initial?: string) =>
+  select('y', findStringColumns(table), initial || 'cpu')
+
 export const fillKnob = (table: Table, initial?: string) =>
   multiSelect('fill', findStringColumns(table), initial || 'cpu')
 
diff --git a/stories/src/index.stories.tsx b/stories/src/index.stories.tsx
index 538b2e01..99ec0e01 100644
--- a/stories/src/index.stories.tsx
+++ b/stories/src/index.stories.tsx
@@ -18,6 +18,7 @@ import {
   PlotContainer,
   xKnob,
   yKnob,
+  yKnobString,
   xScaleKnob,
   yScaleKnob,
   fillKnob,
@@ -417,7 +418,7 @@ storiesOf('XY Plot', module)
     const table = tableKnob()
     const colors = colorSchemeKnob()
     const x = xKnob(table)
-    const y = yKnob(table, 'cpu')
+    const y = yKnobString(table, 'cpu')
     const fill = ['_value']
     const symbol = symbolKnob(table, 'host')