diff --git a/cart-grain-pool.go b/cart-grain-pool.go
index 54f54f1..1da0173 100644
--- a/cart-grain-pool.go
+++ b/cart-grain-pool.go
@@ -465,6 +465,9 @@ func (p *CartPool) getOrClaimGrain(id uint64) (*CartGrain, error) {
 	if err != nil {
 		return nil, err
 	}
+	p.localMu.Lock()
+	p.grains[id] = grain
+	p.localMu.Unlock()
 	go p.broadcastOwnership([]uint64{id})
 	return grain, nil
 }