I hate to be that guy, but the 1L bottle of Los Cinco Sols vanilla I have in my kitchen is not technically pure vanilla extract. Actually, they don't claim that it is. From their website:
Our vanilla is composed of : Purified water, cane alcohol 8%, vegetable glycerin, natural vanillin, vanilla extract and natural caramel.
99% of vanillin is synthetic and made from petrolium, so if true it's great that they use "natural" vanillin. However, pure vanilla extract is over 35% alcohol and doesn't included sweeteners or coloring agents. Vegetable glycerin and caramel are sweeteners, and the caramel helps with the coloring.
Not saying there's anything wrong with LCS Vanilla (we like it), but if you find a real pure vanilla extract expect to pay 6 or 7 times what LCS charges for theirs.