diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index e67f4e359..bc3fafa35 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -556,7 +556,7 @@ void Store::pathInfoToJSON(JSONPlaceholder & jsonOut, const StorePathSet & store
                     if (!narInfo->url.empty())
                         jsonPath.attr("url", narInfo->url);
                     if (narInfo->fileHash)
-                        jsonPath.attr("downloadHash", narInfo->fileHash.to_string(Base32, true));
+                        jsonPath.attr("downloadHash", narInfo->fileHash.to_string(hashBase, true));
                     if (narInfo->fileSize)
                         jsonPath.attr("downloadSize", narInfo->fileSize);
                     if (showClosureSize)