diff --git a/src/utils.jl b/src/utils.jl
index c26e1c2..be1511f 100644
--- a/src/utils.jl
+++ b/src/utils.jl
@@ -31,7 +31,7 @@ function hash_sparse_matrix(H::SparseMatrixCSC)
     write(io, H.rowval)
     write(io, H.nzval)
 
-    update!(ctx, io.data)
+    update!(ctx, take!(io))
 
     return digest!(ctx)
 end