What is the 'malty' flavour added to tea to make it taste like biscuits?
Not something I've ever tried, but I'd be tempted towards either the bottled malt drinks popular in the Caribbean (eg Supermalt), or Horlicks.
Or, you can just buy &quot;malt flavour&quot; - Random google search  for liquid flavour manufacturers - http://www.weberflavors.com/products/liquid-flavors/
Perhaps your 'crumby' malt could be done as a separate infusion first, then just the liquid transferred to the tea.
btw, those tea-bags are about £1.50 in the UK - you could probably find a cheaper supplier than Amazon US ;)