Every beer in the world is an ale or a lager, and everything else is a variation on those two. The split has nothing to do with colour, strength or bitterness, all of which people assume. A stout can be a lager and a pale beer can be an ale. The only thing that separates the two families is the yeast and the temperature it works at.
That is the taxonomy, and you can get it from anywhere. The part that is harder to find is what each style actually does to you, so this page has both.
Ales versus lagers
Ales ferment with Saccharomyces cerevisiae, a top-fermenting yeast that works warm, roughly 60 to 72°F. It is fast, and warm fermentation throws off esters and phenols, which is where the fruity, spicy, banana and clove notes in ales come from. Those compounds are flavour, and they are also fermentation byproducts your body has to process.
Lagers ferment with Saccharomyces pastorianus, a bottom-fermenting yeast that works cold, roughly 45 to 55°F, and then conditions cold for weeks. “Lager” is German for “to store” and the storage is the point. Cold and slow produces far fewer byproducts, which is why lagers taste clean and crisp rather than fruity.
That difference is the single most useful thing to know about beer, for taste and for chemistry both. Cold fermentation makes fewer of the compounds implicated in beer hangovers, and lagers are more often filtered afterwards, which strips out yeast and protein as well.
How to read that table
Our hangover index is the Hang column: 1 to 10, weighting congeners, biogenic amines, polyphenols and ethanol dose, lower being lighter. Load beside it is the flat mean of the seven chemistry factors, which is why the two columns sometimes disagree. A style can be moderate on everything and land mid-table, or be clean apart from one spike and land in the same place for a completely different reason.
Read the top and bottom of it and it looks like a strength ranking. Read the middle and it stops being one.
The four things that actually move the number
Alcohol dose. Still the biggest single term, and the reason non-alcoholic beer scores a 1 and a Belgian tripel scores an 8. A tripel gets to 9% with added candi sugar, so a single 12oz pour delivers more than twice the ethanol of a light lager.
Biogenic amines. Histamine and tyramine, produced by yeast and, much more so, by bacteria. This is the factor that breaks the strength ranking. A sour ale at 4.5% scores a 7 while a pilsner at exactly the same 4.5% scores a 5, because souring means deliberately fermenting with Lactobacillus, Pediococcus and often Brettanomyces, and that bacterial activity generates amines far beyond what brewing yeast alone produces. If beer gives you flushing or a headache rather than a standard hangover, amines are the usual culprit and sours are the worst offenders.
Filtration and wheat. Hefeweizen is 5.4%, the same as an amber ale, and scores a point worse. It is a wheat beer, served unfiltered, so the proteins and yeast that make it cloudy and full stay in the glass. Hazy IPAs work the same way. Cloudiness is protein, and protein is load.
Hop polyphenols. IPAs run 40 to 70 IBU and carry a heavy dose of hop-derived polyphenols and iso-alpha acids on top of a higher ABV. At 6.5% and heavily hopped, an IPA is doing two things at once.
What this means at the bar
If you are choosing beer on how you will feel:
- Non-alcoholic genuinely wins, and modern NA beer is drinkable in a way it was not ten years ago. Under 0.5% ABV, it scores a 1.
- A filtered light or adjunct lager is the best full-strength option. Low alcohol, cold fermented, filtered, low amine.
- A pilsner is the best-tasting beer that is still genuinely light. It scores a 5, mid-table, and it is a real beer rather than a compromise.
- Skip the sour if you get beer headaches. This is the most actionable line on the page, because the amine load is invisible and the ABV is reassuringly low.
- Treat a tripel like wine. At 9% a 12oz pour is closer to two beers than one, and Belgian strong ales are dangerously smooth for their strength.
And the caveat that outweighs all five: beer is the category where volume dominates everything. A 4.2% light lager is the lightest full-strength beer here, and six of them deliver more ethanol than a large glass of wine. The style ranking tells you which beer is easier per serving. It does not tell you that the sixth one is fine.
For the full per-style chemistry breakdown, including biogenic amines, polyphenols and gluten, see the healthiest beer rankings. If you are comparing beer against other categories, the hangover index puts all thirteen side by side, and weakest to strongest covers strength specifically.