diff --git a/Cargo.lock b/Cargo.lock
index a1527c31c..ef9ac5de7 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2148,8 +2148,7 @@ checksum = "d2fabcfbdc87f4758337ca535fb41a6d701b65693ce38287d856d1674551ec9b"
 [[package]]
 name = "grenad"
 version = "0.4.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6a007932af5475ebb5c63bef8812bb1c36f317983bb4ca663e9d6dd58d6a0f8c"
+source = "git+https://github.com/meilisearch/grenad.git?branch=keep-source-index-in-merger#5a7c10fcd689f5967a8979f6b66da1e0939439ff"
 dependencies = [
  "bytemuck",
  "byteorder",
diff --git a/milli/Cargo.toml b/milli/Cargo.toml
index 1dfa495ea..dfb9b34ec 100644
--- a/milli/Cargo.toml
+++ b/milli/Cargo.toml
@@ -26,7 +26,7 @@ flatten-serde-json = { path = "../flatten-serde-json" }
 fst = "0.4.7"
 fxhash = "0.2.1"
 geoutils = "0.5.1"
-grenad = { version = "0.4.5", default-features = false, features = [
+grenad = { git = "https://github.com/meilisearch/grenad.git", branch = "keep-source-index-in-merger", version = "0.4.5", default-features = false, features = [
     "rayon",
     "tempfile",
 ] }