Gonna echo what everyone else is saying and recommend you let them sit for a while. larger quantities may take longer to steep which may explain why the smaller samplers taste good off the shelf.
try putting some of your large bottle liquid in a much smaller bottle and let it sit over a night or two. If that doesn't fix your problem then yah you may want to contact the vendor.
try putting some of your large bottle liquid in a much smaller bottle and let it sit over a night or two. If that doesn't fix your problem then yah you may want to contact the vendor.