diff --git a/src/storage/conversion/ConversionUtil.ts b/src/storage/conversion/ConversionUtil.ts
index 188fbbc38..b13d2fc0d 100644
--- a/src/storage/conversion/ConversionUtil.ts
+++ b/src/storage/conversion/ConversionUtil.ts
@@ -1,5 +1,6 @@
 import type { RepresentationPreference } from '../../ldp/representation/RepresentationPreference';
 import type { RepresentationPreferences } from '../../ldp/representation/RepresentationPreferences';
+import { INTERNAL_ALL } from '../../util/ContentTypes';
 import { InternalServerError } from '../../util/errors/InternalServerError';
 import { UnsupportedHttpError } from '../../util/errors/UnsupportedHttpError';
 import { matchingMediaType } from '../../util/Util';
@@ -8,6 +9,9 @@ import type { RepresentationConverterArgs } from './RepresentationConverter';
 /**
  * Filters media types based on the given preferences.
  * Based on RFC 7231 - Content negotiation.
+ * Will add a default `internal/*;q=0` to the preferences to prevent accidental use of internal types.
+ * Since more specific media ranges override less specific ones,
+ * this will be ignored if there is a specific internal type preference.
  *
  * @param preferences - Preferences for output type.
  * @param types - Media types to compare to the preferences.
@@ -31,6 +35,11 @@ RepresentationPreference[] => {
     return map;
   }, {});
 
+  // Prevent accidental use of internal types
+  if (!prefMap[INTERNAL_ALL]) {
+    prefMap[INTERNAL_ALL] = 0;
+  }
+
   // RFC 7231
   //    Media ranges can be overridden by more specific media ranges or
   //    specific media types.  If more than one media range applies to a
diff --git a/src/util/ContentTypes.ts b/src/util/ContentTypes.ts
index 3c22a6e75..f4fdf0f48 100644
--- a/src/util/ContentTypes.ts
+++ b/src/util/ContentTypes.ts
@@ -4,4 +4,5 @@ export const APPLICATION_OCTET_STREAM = 'application/octet-stream';
 export const APPLICATION_SPARQL_UPDATE = 'application/sparql-update';
 
 // Internal (non-exposed) content types
+export const INTERNAL_ALL = 'internal/*';
 export const INTERNAL_QUADS = 'internal/quads';
diff --git a/test/unit/storage/conversion/ConversionUtil.test.ts b/test/unit/storage/conversion/ConversionUtil.test.ts
index b4f39346e..d2007f033 100644
--- a/test/unit/storage/conversion/ConversionUtil.test.ts
+++ b/test/unit/storage/conversion/ConversionUtil.test.ts
@@ -19,22 +19,22 @@ describe('A ConversionUtil', (): void => {
   describe('#checkRequest', (): void => {
     it('requires an input type.', async(): Promise<void> => {
       const preferences: RepresentationPreferences = {};
-      expect((): any => checkRequest({ identifier, representation, preferences }, [ '*/*' ], [ '*/*' ]))
+      expect((): any => checkRequest({ identifier, representation, preferences }, [ 'a/x' ], [ 'a/x' ]))
         .toThrow('Input type required for conversion.');
     });
 
     it('requires a matching input type.', async(): Promise<void> => {
       metadata.contentType = 'a/x';
       const preferences: RepresentationPreferences = { type: [{ value: 'b/x', weight: 1 }]};
-      expect((): any => checkRequest({ identifier, representation, preferences }, [ 'c/x' ], [ '*/*' ]))
-        .toThrow('Can only convert from c/x to */*.');
+      expect((): any => checkRequest({ identifier, representation, preferences }, [ 'c/x' ], [ 'a/x' ]))
+        .toThrow('Can only convert from c/x to a/x.');
     });
 
     it('requires a matching output type.', async(): Promise<void> => {
       metadata.contentType = 'a/x';
       const preferences: RepresentationPreferences = { type: [{ value: 'b/x', weight: 1 }]};
-      expect((): any => checkRequest({ identifier, representation, preferences }, [ '*/*' ], [ 'c/x' ]))
-        .toThrow('Can only convert from */* to c/x.');
+      expect((): any => checkRequest({ identifier, representation, preferences }, [ 'a/x' ], [ 'c/x' ]))
+        .toThrow('Can only convert from a/x to c/x.');
     });
 
     it('succeeds with a valid input and output type.', async(): Promise<void> => {
@@ -48,7 +48,7 @@ describe('A ConversionUtil', (): void => {
   describe('#matchingTypes', (): void => {
     it('requires type preferences.', async(): Promise<void> => {
       const preferences: RepresentationPreferences = {};
-      expect((): any => matchingTypes(preferences, [ '*/*' ]))
+      expect((): any => matchingTypes(preferences, [ 'a/b' ]))
         .toThrow('Output type required for conversion.');
     });
 
@@ -71,5 +71,24 @@ describe('A ConversionUtil', (): void => {
       expect((): any => matchingTypes(preferences, [ 'noType' ]))
         .toThrow(new InternalServerError(`Unexpected type preference: noType`));
     });
+
+    it('filters out internal types.', async(): Promise<void> => {
+      const preferences: RepresentationPreferences = { type: [{ value: '*/*', weight: 1 }]};
+      expect(matchingTypes(preferences, [ 'a/x', 'internal/quads' ])).toEqual([{ value: 'a/x', weight: 1 }]);
+    });
+
+    it('keeps internal types that are specifically requested.', async(): Promise<void> => {
+      const preferences: RepresentationPreferences =
+        { type: [{ value: '*/*', weight: 1 }, { value: 'internal/*', weight: 0.5 }]};
+      expect(matchingTypes(preferences, [ 'a/x', 'internal/quads' ]))
+        .toEqual([{ value: 'a/x', weight: 1 }, { value: 'internal/quads', weight: 0.5 }]);
+    });
+
+    it('takes the most relevant weight for a type.', async(): Promise<void> => {
+      const preferences: RepresentationPreferences =
+        { type: [{ value: '*/*', weight: 1 }, { value: 'internal/quads', weight: 0.5 }]};
+      expect(matchingTypes(preferences, [ 'a/x', 'internal/quads' ]))
+        .toEqual([{ value: 'a/x', weight: 1 }, { value: 'internal/quads', weight: 0.5 }]);
+    });
   });
 });