diff --git a/pyproject.toml b/pyproject.toml
index b21262a..1b434f3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -28,7 +28,7 @@ parquet = [
 ]
 xarray = [
     "xarray>=2026.04",
-    "zarr~=3.1.6",
+    "zarr>=3.1.6,<3.4",
     "zarrs>=0.2",
     "pint",
     "unum",
@@ -41,7 +41,7 @@ dev = [
     "fsspec",
     "tqdm",
     "xarray>=2026.04",
-    "zarr~=3.1.6",
+    "zarr>=3.1.6,<3.4",
     "zarrs>=0.2",
     "pint",
     "unum",
diff --git a/uv.lock b/uv.lock
index 0ec03b4..549b45f 100644
--- a/uv.lock
+++ b/uv.lock
@@ -1505,7 +1505,7 @@ wheels = [
 
 [[package]]
 name = "viva-emitters"
-version = "0.2.1"
+version = "0.2.3"
 source = { editable = "." }
 dependencies = [
     { name = "bigraph-schema" },
@@ -1564,8 +1564,8 @@ requires-dist = [
     { name = "unum", marker = "extra == 'xarray'" },
     { name = "xarray", marker = "extra == 'dev'", specifier = ">=2026.4" },
     { name = "xarray", marker = "extra == 'xarray'", specifier = ">=2026.4" },
-    { name = "zarr", marker = "extra == 'dev'", specifier = "~=3.1.6" },
-    { name = "zarr", marker = "extra == 'xarray'", specifier = "~=3.1.6" },
+    { name = "zarr", marker = "extra == 'dev'", specifier = ">=3.1.6,<3.4" },
+    { name = "zarr", marker = "extra == 'xarray'", specifier = ">=3.1.6,<3.4" },
     { name = "zarrs", marker = "extra == 'dev'", specifier = ">=0.2" },
     { name = "zarrs", marker = "extra == 'xarray'", specifier = ">=0.2" },
 ]
diff --git a/viva_emitters/xarray_emitter/zarr_writer.py b/viva_emitters/xarray_emitter/zarr_writer.py
index 77bdd2e..7218aed 100644
--- a/viva_emitters/xarray_emitter/zarr_writer.py
+++ b/viva_emitters/xarray_emitter/zarr_writer.py
@@ -156,8 +156,11 @@ async def consolidate_metadata(
         k: v.metadata
         async for (k, v) in
         group.members(max_depth=None, use_consolidated_for_children=False)}
-    # TODO: fix in `consolidate_metadata()` (zarr==3.1.6)
-    members_metadata |= {"": group.metadata}
+    # The root node is STRICTLY EXCLUDED from consolidated metadata: a "" entry
+    # is a self-reference that risks infinite loops in Zarr traversal functions
+    # (e.g. Group.tree()), not only ConsolidatedMetadata._flat_to_nested(). The
+    # root's own metadata lives on `group` itself. (Per @ntfrgl on PR #31;
+    # mirrors vEcoli be603b5d.)
 
     # combine and write consolidated metadata
     for k, v in members_metadata.items():
@@ -208,11 +211,14 @@ async def reconsolidate_metadata(
     # read metadata at updated paths
     group = _replace_consolidated_metadata(group, None)
     mod_members_metadata, add_members_metadata = [
-        {k: n.metadata async for (k, n) in _iter_from_keys(group, keys)}
+        # `if k` strictly excludes the root node: a "" entry is a self-reference
+        # that risks infinite loops in Zarr traversal functions (see
+        # consolidate_metadata above).
+        {k: n.metadata async for (k, n) in _iter_from_keys(group, keys) if k}
         for keys in [modified_keys, added_keys]]
 
     # check assumptions about metadata updates
-    old_keys = set(members_metadata.keys()) | {""}
+    old_keys = set(members_metadata.keys())
     assert set(mod_members_metadata.keys()).issubset(old_keys)
     assert set(add_members_metadata.keys()).isdisjoint(old_keys)