Beer is wonderfully complex and relatively short lived compared to wine. So always demand fresh beer for the full hop flavour. Draft beer is better than bottled!

A wonderful complex flavour of hops and malt and yeast flavours. I never realized hops could have such a complex aroma

The flavour of beer comes from the hops,malt and fermentation process. The hops are a complex flavour of water soluble isohumulones (bitter acids derived from hops) and hop oil derived from the volatile components of hops. If you want a more bitterness the hops need to be extracted longer and if you wish more aroma then you need to extract the hops quickly and possibly after fermentation to decrease aroma losses.

Bottled beer looses this nice hop aroma with time so fresh draft is often regarded as better.

The wonderful world of Hops    Hop oil and extract                      

Beer Academy

Beer flavour      

More         on Beer Flavour

Sensory analysis of beer

Beer high impact aromas

Beer Flavour 

I have seen many articles about the safety of flavour chemicals and flavour ingredients.

Most of the ingredients used in the flavour industry by volume are natural essential oils. Flavour chemicals are often chemical duplicates of those found in nature.(called nature identical) There is a relatively small number of exclusively artificial chemicals.

So the question is how safe?

 In the USA you can only use substances listed on the FEMA GRAS list. (see Legal)

When you look at nature it is often the concentration rather than the chemical that is the problem. Ethanethiol found in durian and added for safety to natural gas is toxic as well as H2S which has an egg aroma at very low concentrations and is toxic at high concentrations.

Acetaldehye found in wine, orange juice and apples is also a problem at high concentrations. Diacetyl is another flavouring with problems at high concentration (see legal)

Caffine is toxic to dogs and snails but we all drink Tea or coffee.

Now before I go on further let me tell you that I am not an expert on this subject so the article is just my opinion.

Most of the problems with aroma chemicals happen in a flavour/perfume  factory where workers are exposed to high concentrations. Even with natural vanilla beans workers exposed to high levels of vanillin have problems.

At the levels in the final food it is difficult to see that there is a problem.

Bread Flavour

I doubt if anyone really knows what components are responsible for bread flavour but the following are often mentioned:-

6-Acetyltetrahydropyridine  FEMA 3251

2-Acetyl-1-pyrroline             FEMA 3202

3-Methylbutanal

Methional                            FEMA 2747

(E)-2-Nonenal

 (E,E)-2,4-Decadienal

2-Ethyl-3,5-dimethylpyrazine FEMA 3149

5-Ethyl-3-hydroxy-4-methyl-2(5H)-furanone  FEMA 3153

How bread is made!

Malt Flavour    Maillard Reactions

Identification of the key odorants in barley malt (caramalt)

Application of the Aroma Extract Dilution Analysis on a distillate prepared from ground caramalt kernels followed by identification experiments revealed 3-methylbutanal (malty), 1-octen-3-one (mushroom-like), methional (cooked potato), (E,E)-2,4-decadienal (fatty, waxy), vanillin (vanilla-like), 2- and 3-methylbutanoic acid (sweaty) and 4-hydroxy-2,5-dimethyl-3(2H)-furanone (caramel-like) as the most odor-active compounds. Using static headspace/olfactometry, the very volatile odorants dimethyl sulfide (cooked vegetable-like) and 2-methylpropanal (malty) were identified as additional odorants contributing to the overall rye-bread crust-like odor of the caramalt