In my catalog/product_list block template (catalog/product/list.phtml), I've this piece of code that should work, but $_productCollection is always false:

 <?php
 $session = Mage::getSingleton('core/session');
 $_productCollection = $session->getProductCollection();
 
 if (!$_productCollection){
 
 $_productCollection=$this->getLoadedProductCollection();
 $session->setProductCollection($_productCollection);
 }
 
 $_helper = $this->helper('catalog/output');

Strings work, just not collection objects it seems. In my IDE I can see the $_SESSION superglobal populating with the collection, but on refresh it just disappears. Maybe is it being garbage collected? Any one have any idea?