diff --git a/internal/experiment/echcheck/handshake.go b/internal/experiment/echcheck/handshake.go
index 05a4e2526..080444cf1 100644
--- a/internal/experiment/echcheck/handshake.go
+++ b/internal/experiment/echcheck/handshake.go
@@ -34,7 +34,9 @@ func handshakeWithEch(ctx context.Context, conn net.Conn, zeroTime time.Time,
 	utlsEchExtension.Id = echExtensionType
 	utlsEchExtension.Data = payload
 
-	return handshakeWithExtension(ctx, conn, zeroTime, address, sni, []utls.TLSExtension{&utlsEchExtension}, logger)
+	hs := handshakeWithExtension(ctx, conn, zeroTime, address, sni, []utls.TLSExtension{&utlsEchExtension}, logger)
+	hs.ECHConfig = "GREASE"
+	return hs
 }
 
 func handshakeMaybePrintWithECH(doprint bool) string {
diff --git a/internal/experiment/echcheck/measure.go b/internal/experiment/echcheck/measure.go
index 1bfe0e2b6..bd1d12ffb 100644
--- a/internal/experiment/echcheck/measure.go
+++ b/internal/experiment/echcheck/measure.go
@@ -16,7 +16,7 @@ import (
 
 const (
 	testName    = "echcheck"
-	testVersion = "0.1.2"
+	testVersion = "0.2.0"
 	defaultURL  = "https://cloudflare-ech.com/cdn-cgi/trace"
 )
 
@@ -30,8 +30,7 @@ var (
 
 // TestKeys contains echcheck test keys.
 type TestKeys struct {
-	Control model.ArchivalTLSOrQUICHandshakeResult `json:"control"`
-	Target  model.ArchivalTLSOrQUICHandshakeResult `json:"target"`
+	TLSHandshakes []*model.ArchivalTLSOrQUICHandshakeResult `json:"tls_handshakes"`
 }
 
 // Measurer performs the measurement.
@@ -124,7 +123,7 @@ func (m *Measurer) Run(
 	control := <-controlChannel
 	target := <-targetChannel
 
-	args.Measurement.TestKeys = TestKeys{Control: control, Target: target}
+	args.Measurement.TestKeys = TestKeys{TLSHandshakes: []*model.ArchivalTLSOrQUICHandshakeResult{&control, &target}}
 
 	return nil
 }
diff --git a/internal/experiment/echcheck/measure_test.go b/internal/experiment/echcheck/measure_test.go
index 2a53fbd93..14ae2b292 100644
--- a/internal/experiment/echcheck/measure_test.go
+++ b/internal/experiment/echcheck/measure_test.go
@@ -114,10 +114,13 @@ func TestMeasurementSuccessRealWorld(t *testing.T) {
 
 	// check results
 	tk := msrmnt.TestKeys.(TestKeys)
-	if tk.Control.Failure != nil {
-		t.Fatal("unexpected control failure:", *tk.Control.Failure)
-	}
-	if tk.Target.Failure != nil {
-		t.Fatal("unexpected target failure:", *tk.Target.Failure)
+	for _, hs := range tk.TLSHandshakes {
+		if hs.Failure != nil {
+			if hs.ECHConfig == "GREASE" {
+				t.Fatal("unexpected exp failure:", hs.Failure)
+			} else {
+				t.Fatal("unexpected ctrl failure:", hs.Failure)
+			}
+		}
 	}
 }
diff --git a/internal/model/archival.go b/internal/model/archival.go
index 8a17e745e..affa15c33 100644
--- a/internal/model/archival.go
+++ b/internal/model/archival.go
@@ -248,6 +248,7 @@ type ArchivalTLSOrQUICHandshakeResult struct {
 	NoTLSVerify        bool                 `json:"no_tls_verify"`
 	PeerCertificates   []ArchivalBinaryData `json:"peer_certificates"`
 	ServerName         string               `json:"server_name"`
+	ECHConfig          string               `json:"echconfig,omitempty"`
 	T0                 float64              `json:"t0,omitempty"`
 	T                  float64              `json:"t"`
 	Tags               []string             `json:"tags"`