diff --git a/server/src/main/java/org/elasticsearch/index/IndexingSlowLog.java b/server/src/main/java/org/elasticsearch/index/IndexingSlowLog.java
index e69cfd2c7af..b4b471e220a 100644
--- a/server/src/main/java/org/elasticsearch/index/IndexingSlowLog.java
+++ b/server/src/main/java/org/elasticsearch/index/IndexingSlowLog.java
@@ -194,7 +194,7 @@ public final class IndexingSlowLog implements IndexingOperationListener {
             }
             try {
                 String source = XContentHelper.convertToJson(doc.source(), reformat, doc.getXContentType());
-                sb.append(", source[").append(Strings.cleanTruncate(source, maxSourceCharsToLog)).append("]");
+                sb.append(", source[").append(Strings.cleanTruncate(source, maxSourceCharsToLog).trim()).append("]");
             } catch (IOException e) {
                 sb.append(", source[_failed_to_convert_[").append(e.getMessage()).append("]]");
                 /*
diff --git a/server/src/test/java/org/elasticsearch/index/IndexingSlowLogTests.java b/server/src/test/java/org/elasticsearch/index/IndexingSlowLogTests.java
index 6bb799ac9eb..72a1cb4a87d 100644
--- a/server/src/test/java/org/elasticsearch/index/IndexingSlowLogTests.java
+++ b/server/src/test/java/org/elasticsearch/index/IndexingSlowLogTests.java
@@ -38,6 +38,7 @@ import java.io.IOException;
 import java.io.UncheckedIOException;
 
 import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasToString;
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.not;
@@ -127,6 +128,22 @@ public class IndexingSlowLogTests extends ESTestCase {
         assertTrue(log.isReformat());
     }
 
+    public void testReformatIsFalseAndSourceIsTrim() {
+        String json = "\n\n{ \"fieldName\": 123 }  \n ";
+        BytesReference source = new BytesArray(json);
+        ParsedDocument pd = new ParsedDocument(new NumericDocValuesField("version", 1),
+            SeqNoFieldMapper.SequenceIDFields.emptySeqID(), "id",
+            "test", null, null, source, XContentType.JSON, null);
+        Index index = new Index("foo", "123");
+        // Turning off reformatting so the document is in logs as provided
+        SlowLogParsedDocumentPrinter p = new SlowLogParsedDocumentPrinter(index, pd, 10, false, 1000);
+        String logLine = p.toString();
+
+        //expect the new lines and white characters to be trimmed
+        assertThat(logLine, containsString("source[{"));
+        assertThat(logLine.split("\n").length, equalTo(1));
+    }
+
     public void testLevelSetting() {
         SlowLogLevel level = randomFrom(SlowLogLevel.values());
         IndexMetaData metaData = newIndexMeta("index", Settings.builder()