diff --git a/src/lib.rs b/src/lib.rs
index 5422284..01371af 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -16,7 +16,6 @@ use serde::{Deserialize, Serialize};
 use serde_big_array::big_array;
 
 /// Parameters for building the `Hnsw`
-#[derive(Default)]
 pub struct Builder {
     ef_search: Option<usize>,
     ef_construction: Option<usize>,
@@ -43,8 +42,8 @@ impl Builder {
         self
     }
 
-    pub fn select_heuristic(mut self, params: Heuristic) -> Self {
-        self.heuristic = Some(params);
+    pub fn select_heuristic(mut self, params: Option<Heuristic>) -> Self {
+        self.heuristic = params;
         self
     }
 
@@ -77,6 +76,20 @@ impl Builder {
     }
 }
 
+impl Default for Builder {
+    fn default() -> Self {
+        Self {
+            ef_search: None,
+            ef_construction: None,
+            heuristic: Some(Heuristic::default()),
+            ml: None,
+            seed: None,
+            #[cfg(feature = "indicatif")]
+            progress: None,
+        }
+    }
+}
+
 #[derive(Copy, Clone, Debug)]
 pub struct Heuristic {
     pub extend_candidates: bool,
diff --git a/tests/all.rs b/tests/all.rs
index 9bdefc3..6e04118 100644
--- a/tests/all.rs
+++ b/tests/all.rs
@@ -25,14 +25,14 @@ fn basic() {
 
 #[test]
 fn random_heuristic() {
-    let (seed, recall) = randomized(Builder::default().select_heuristic(Heuristic::default()));
+    let (seed, recall) = randomized(Builder::default());
     println!("heuristic (seed = {}) recall = {}", seed, recall);
     assert!(recall > 98, "expected at least 98, got {}", recall);
 }
 
 #[test]
 fn random_simple() {
-    let (seed, recall) = randomized(Builder::default());
+    let (seed, recall) = randomized(Builder::default().select_heuristic(None));
     println!("simple (seed = {}) recall = {}", seed, recall);
     assert!(recall > 90, "expected at least 90, got {}", recall);
 }