diff --git a/src/runtime/c/pgf/literals.c b/src/runtime/c/pgf/literals.c
index e6c9a9ed3..e1c9ad880 100644
--- a/src/runtime/c/pgf/literals.c
+++ b/src/runtime/c/pgf/literals.c
@@ -176,13 +176,14 @@ static bool
 pgf_match_name_lit(PgfConcr* concr, PgfItem* item, PgfToken tok,
                    PgfExprProb** out_ep, GuPool *pool)
 {
+	GuPool* tmp_pool = gu_new_pool();
+
 	size_t lin_idx;
 	PgfSequence seq;
-	pgf_item_sequence(item, &lin_idx, &seq, pool);
+	pgf_item_sequence(item, &lin_idx, &seq, tmp_pool);
 
 	gu_assert(lin_idx == 0);
 
-	GuPool* tmp_pool = gu_new_pool();
 	GuExn* err = gu_new_exn(NULL, gu_kind(type), tmp_pool);
 	
 	GuString hyp = gu_str_string("-", tmp_pool);
diff --git a/src/runtime/c/pgf/parser.c b/src/runtime/c/pgf/parser.c
index ba75b965f..2d1432f20 100644
--- a/src/runtime/c/pgf/parser.c
+++ b/src/runtime/c/pgf/parser.c
@@ -44,7 +44,8 @@ typedef GuBuf PgfCCatBuf;
 
 typedef struct {
 	PgfConcr* concr;
-	GuPool* pool;
+	GuPool* pool;      // this pool is used for structures internal to the parser
+	GuPool* out_pool;  // this pool is used for the allocating the final abstract trees
 	GuBuf* expr_queue;
 	PgfExpr meta_var;
 	PgfProduction meta_prod;
@@ -119,7 +120,6 @@ typedef struct {
 typedef struct PgfParseResult PgfParseResult;
 
 struct PgfParseResult {
-	GuPool* tmp_pool;
     PgfParseState* state;
 	PgfExprEnum en;
 };
@@ -1496,7 +1496,7 @@ pgf_parsing_item(PgfParseState* before, PgfParseState* after, PgfItem* item)
 			bool accepted = 
 				pext->callback->match(before->ps->concr, item, 
 				                      tok,
-				                      &ep, before->ps->pool);
+				                      &ep, before->ps->out_pool);
 
 			if (ep != NULL)
 				pgf_parsing_complete(before, after, item, ep);
@@ -1643,6 +1643,7 @@ pgf_new_parsing(PgfConcr* concr, GuPool* pool)
 	PgfParsing* ps = gu_new(PgfParsing, pool);
 	ps->concr = concr;
 	ps->pool = pool;
+	ps->out_pool = NULL;
 	ps->expr_queue = gu_new_buf(PgfExprState*, pool);
 	ps->max_fid = concr->total_cats;
 #ifdef PGF_COUNTS_DEBUG
@@ -2011,9 +2012,10 @@ pgf_result_predict(PgfParsing* ps,
 			PgfExprState* st = gu_new(PgfExprState, ps->pool);
 			st->answers = cont->answers;
 			st->ep.expr =
-				gu_new_variant_i(ps->pool, PGF_EXPR_APP,
-						PgfExprApp,
-						.fun = cont->ep.expr, .arg = ep->expr);
+				gu_new_variant_i(ps->out_pool, 
+				                 PGF_EXPR_APP, PgfExprApp,
+						         .fun = cont->ep.expr,
+						         .arg = ep->expr);
 			st->ep.prob = cont->ep.prob+ep->prob;
 			st->args    = cont->args;
 			st->arg_idx = cont->arg_idx+1;
@@ -2024,7 +2026,7 @@ pgf_result_predict(PgfParsing* ps,
 }
 
 static PgfExprProb*
-pgf_parse_result_next(PgfParseResult* pr, GuPool* pool)
+pgf_parse_result_next(PgfParseResult* pr)
 {
 	for (;;) {
 		while (pgf_parsing_proceed(pr->state));
@@ -2052,8 +2054,8 @@ pgf_parse_result_next(PgfParseResult* pr, GuPool* pool)
 
 			if (ccat->fid < pr->state->ps->concr->total_cats) {
 				st->ep.expr =
-					gu_new_variant_i(pool, PGF_EXPR_APP,
-									 PgfExprApp,
+					gu_new_variant_i(pr->state->ps->out_pool, 
+					                 PGF_EXPR_APP, PgfExprApp,
 									 .fun = st->ep.expr,
 									 .arg = pr->state->ps->meta_var);
 				st->arg_idx++;
@@ -2075,9 +2077,10 @@ pgf_parse_result_next(PgfParseResult* pr, GuPool* pool)
 				PgfExprState* st3 = gu_new(PgfExprState, pr->state->ps->pool);
 				st3->answers = st2->answers;
 				st3->ep.expr =
-					gu_new_variant_i(pr->state->ps->pool, PGF_EXPR_APP,
-							PgfExprApp,
-							.fun = st2->ep.expr, .arg = st->ep.expr);
+					gu_new_variant_i(pr->state->ps->out_pool,
+					                 PGF_EXPR_APP, PgfExprApp,
+							         .fun = st2->ep.expr,
+							         .arg = st->ep.expr);
 				st3->ep.prob = st2->ep.prob + st->ep.prob;
 				st3->args = st2->args;
 				st3->arg_idx = st2->arg_idx+1;
@@ -2094,7 +2097,7 @@ static void
 pgf_parse_result_enum_next(GuEnum* self, void* to, GuPool* pool)
 {
 	PgfParseResult* pr = gu_container(self, PgfParseResult, en);
-	*(PgfExprProb**)to = pgf_parse_result_next(pr, pool);
+	*(PgfExprProb**)to = pgf_parse_result_next(pr);
 }
 
 PgfExprEnum*
@@ -2104,11 +2107,10 @@ pgf_parse_result(PgfParseState* state, GuPool* pool)
 	pgf_parsing_print_counts(state->ps);
 #endif
 
-	GuPool* tmp_pool = gu_new_pool();
+	state->ps->out_pool = pool;
 
 	PgfExprEnum* en =
            &gu_new_i(pool, PgfParseResult,
-			 .tmp_pool = tmp_pool,
              .state = state,
 			 .en.next = pgf_parse_result_enum_next)->en;
 
diff --git a/src/runtime/c/pgf/pgf.c b/src/runtime/c/pgf/pgf.c
index 24d330981..b355593d8 100644
--- a/src/runtime/c/pgf/pgf.c
+++ b/src/runtime/c/pgf/pgf.c
@@ -207,7 +207,8 @@ pgf_linearize(PgfConcr* concr, PgfExpr expr, GuWriter* wtr, GuExn* err)
 }
 
 GuEnum*
-pgf_parse(PgfConcr* concr, PgfCId cat, PgfLexer *lexer, GuPool* pool)
+pgf_parse(PgfConcr* concr, PgfCId cat, PgfLexer *lexer, 
+          GuPool* pool, GuPool* out_pool)
 {
 	// Begin parsing a sentence of the specified category
 	PgfParseState* state =
@@ -233,7 +234,7 @@ pgf_parse(PgfConcr* concr, PgfCId cat, PgfLexer *lexer, GuPool* pool)
 		return NULL;
 
 	// Now begin enumerating the resulting syntax trees
-	return pgf_parse_result(state, pool);
+	return pgf_parse_result(state, out_pool);
 }
 
 GuEnum*
diff --git a/src/runtime/c/pgf/pgf.h b/src/runtime/c/pgf/pgf.h
index 39dc0dd04..d83598cc0 100644
--- a/src/runtime/c/pgf/pgf.h
+++ b/src/runtime/c/pgf/pgf.h
@@ -114,7 +114,8 @@ void
 pgf_linearize(PgfConcr* concr, PgfExpr expr, GuWriter* wtr, GuExn* err);
 
 PgfExprEnum*
-pgf_parse(PgfConcr* concr, PgfCId cat, PgfLexer *lexer, GuPool* pool);
+pgf_parse(PgfConcr* concr, PgfCId cat, PgfLexer *lexer, 
+          GuPool* pool, GuPool* out_pool);
 
 GuEnum*
 pgf_get_completions(PgfConcr* concr, PgfCId cat, PgfLexer *lexer, 
diff --git a/src/runtime/c/utils/pgf-parse.c b/src/runtime/c/utils/pgf-parse.c
index 648295312..32f979ce0 100644
--- a/src/runtime/c/utils/pgf-parse.c
+++ b/src/runtime/c/utils/pgf-parse.c
@@ -124,7 +124,7 @@ int main(int argc, char* argv[]) {
 
     GuReader *rdr = gu_string_reader(gu_str_string(line, ppool), ppool);
     PgfLexer *lexer = pgf_new_simple_lexer(rdr, ppool);
-    GuEnum* result = pgf_parse(concr, cat, lexer, ppool);
+    GuEnum* result = pgf_parse(concr, cat, lexer, ppool, ppool);
 
     PgfExprProb* ep = NULL;
     if (result != NULL) 
diff --git a/src/runtime/c/utils/pgf-service.c b/src/runtime/c/utils/pgf-service.c
index 94070efee..33369b9f5 100644
--- a/src/runtime/c/utils/pgf-service.c
+++ b/src/runtime/c/utils/pgf-service.c
@@ -335,7 +335,7 @@ int main ()
 				pgf_new_simple_lexer(rdr, ppool);
 
 			GuEnum* result = 
-				pgf_parse(from_concr, cat, lexer, ppool);
+				pgf_parse(from_concr, cat, lexer, ppool, ppool);
 			if (result == NULL) {
 				FCGI_printf("Status: 500 Internal Server Error\r\n");
 				FCGI_printf("Content-type: text/plain\r\n"
diff --git a/src/runtime/c/utils/pgf-translate.c b/src/runtime/c/utils/pgf-translate.c
index e58b9d282..f53a847e3 100644
--- a/src/runtime/c/utils/pgf-translate.c
+++ b/src/runtime/c/utils/pgf-translate.c
@@ -169,7 +169,7 @@ int main(int argc, char* argv[]) {
 		clock_t start = clock();
 
 		result =
-			pgf_parse(from_concr, cat, lexer, ppool);
+			pgf_parse(from_concr, cat, lexer, ppool, ppool);
 		if (result == NULL) {
 			PgfToken tok =
 				pgf_lexer_current_token(lexer);
diff --git a/src/runtime/python/pypgf.c b/src/runtime/python/pypgf.c
index f9428f96d..de5ead10f 100644
--- a/src/runtime/python/pypgf.c
+++ b/src/runtime/python/pypgf.c
@@ -435,6 +435,7 @@ Expr_getattro(ExprObject *self, PyObject *attr_name) {
 typedef struct IterObject {
     PyObject_HEAD
     PGFObject* grammar;
+    PyObject* container;
     GuPool* pool;
     int max_count;
     int counter;
@@ -454,8 +455,8 @@ Iter_fetch_expr(IterObject* self)
 		return NULL;
 	pyexpr->pool   = NULL;
 	pyexpr->expr   = ep->expr;
-	pyexpr->master = (PyObject*) self;
-	Py_INCREF(self);
+	pyexpr->master = self->container;
+	Py_INCREF(self->container);
 
 	PyObject* res = Py_BuildValue("(f,O)", ep->prob, pyexpr);
 	Py_DECREF(pyexpr);
@@ -483,6 +484,7 @@ Iter_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
     IterObject* self = (IterObject *)type->tp_alloc(type, 0);
     if (self != NULL) {
 		self->grammar = NULL;
+		self->container = NULL;
 		self->pool = NULL;
 		self->max_count = -1;
 		self->counter   = 0;
@@ -499,6 +501,8 @@ Iter_dealloc(IterObject* self)
 		gu_pool_free(self->pool);
 
 	Py_XDECREF(self->grammar);
+	
+	Py_XDECREF(self->container);
 
     self->ob_type->tp_free((PyObject*)self);
 }
@@ -661,6 +665,14 @@ pypgf_new_python_lexer(PyObject* pylexer, GuPool* pool)
 	return ((PgfLexer*) lexer);
 }
 
+#define PGF_CONTAINER_NAME "pgf.Container"
+
+void pypgf_container_descructor(PyObject *capsule)
+{
+	GuPool* pool = PyCapsule_GetPointer(capsule, PGF_CONTAINER_NAME);
+	gu_pool_free(pool);
+}
+
 static IterObject*
 Concr_parse(ConcrObject* self, PyObject *args, PyObject *keywds)
 {
@@ -698,28 +710,35 @@ Concr_parse(ConcrObject* self, PyObject *args, PyObject *keywds)
 	pyres->grammar = self->grammar;
 	Py_XINCREF(pyres->grammar);
 
-	pyres->pool = gu_new_pool();
+	GuPool* out_pool = gu_new_pool();
+	
+	PyObject* py_pool =
+		PyCapsule_New(out_pool, PGF_CONTAINER_NAME, 
+		              pypgf_container_descructor);
+	pyres->container = PyTuple_Pack(2, pyres->grammar, py_pool);
+	Py_DECREF(py_pool);
+
+	pyres->pool      = gu_new_pool();
 	pyres->max_count = max_count;
 	pyres->counter   = 0;
 	pyres->fetch     = Iter_fetch_expr;
 
-	GuPool *tmp_pool = gu_local_pool();
     GuString catname =
-		(catname_s == NULL) ? pgf_start_cat(self->grammar->pgf, tmp_pool)
-		                    : gu_str_string(catname_s, tmp_pool);
+		(catname_s == NULL) ? pgf_start_cat(self->grammar->pgf, pyres->pool)
+		                    : gu_str_string(catname_s, pyres->pool);
 
 	PgfLexer *lexer = NULL;
 	if (buf != NULL) {
-		GuIn* in = gu_data_in(buf, len, tmp_pool);
-		GuReader* rdr = gu_new_utf8_reader(in, tmp_pool);
-		lexer = pgf_new_simple_lexer(rdr, tmp_pool);
+		GuIn* in = gu_data_in(buf, len, pyres->pool);
+		GuReader* rdr = gu_new_utf8_reader(in, pyres->pool);
+		lexer = pgf_new_simple_lexer(rdr, pyres->pool);
 	} 
 	if (py_lexer != NULL) {
-		lexer = pypgf_new_python_lexer(py_lexer, tmp_pool);
+		lexer = pypgf_new_python_lexer(py_lexer, pyres->pool);
 	}
 
 	pyres->res =
-		pgf_parse(self->concr, catname, lexer, pyres->pool);
+		pgf_parse(self->concr, catname, lexer, pyres->pool, out_pool);
 
 	if (pyres->res == NULL) {
 		Py_DECREF(pyres);
@@ -740,7 +759,6 @@ Concr_parse(ConcrObject* self, PyObject *args, PyObject *keywds)
 	}
 
 	Py_XDECREF(py_lexer);
-	gu_pool_free(tmp_pool);
 
 	return pyres;
 }
@@ -784,6 +802,8 @@ Concr_getCompletions(ConcrObject* self, PyObject *args, PyObject *keywds)
 
 	pyres->grammar = self->grammar;
 	Py_XINCREF(pyres->grammar);
+	
+	pyres->container = NULL;
 
 	pyres->pool = gu_new_pool();
 	pyres->max_count = max_count;