Homebrew: Beer yeasts
As with all recipes to create great beer you need the best ingredients for
the job. Whilst those new to homebrewing often use general beer yeasts (or indeed
whatever is at hand!), besides good malts, hops and glucose based brewing sugar,
those refining their talents know to selectvely use the correct beer yeast designed
specifically for whatever they're fermenting.
About beer yeast
Yeast is a live, active fungus. Each packet contains litterally bilions of yeast
cells, which under the right conditions
i.e. damp and a little wamth, feed on sugar and multiply. As the yeast feeds on
the sugar in your fermentation it creates it's byproduct... alcohol.
Hey-presto! The homebrewer is spoilt for choice today as there is a complete range
of reproduced yeasts available today through homebrew shops of yeasts from all over
the world.
Re-activing dried yeasts
Dried yeasts are widely used as they are both simple to use and more cost effective.
For a better though outcome, rather than pitching dried yeast, rehydrate the
dried yeast to fully re-activate it. Sterilise tea/coffee flask, pop your yeast
in and add 75ml of purified water at a temperature of around 40°C (104°F),
this is best done by boiling and then adding the cooling water at the appropriate
temperature. Shake gently, let stand for 10-15 minutes, shake gently again before
adding to your brew to start fermentation.
Using liquid yeast cultures
The best yeasts to use however are liquid yeast cultures. These usually come
foil packed to avoid air contact and separately contains both the yeast and
the yeast nutrients. Upon preparation the seal between the two is broken, the
packet is mixed though kneading the ingredients. After leaving in a warm place
for a short time (as per instructions) the packet will expand as the yeast actively
thrives ready for pitching.
Yeasts used to make lager
Lagers obviously have a crisper, delicate flavour than other beers. It is perhaps
unsurpirsing therefore that lager yeasts ferment at lower temperatures (circa 45°
and 50°F [7° to 10°C]) ferment for more gently but over longer periods.
Yeasts used to make ale
Ales are typified by having a deeper and wider variation of colour, flavour
and aroma than lagers. This is created by having a much bigger array of potential
yeasts (& other ingredients) to choose from and greater tolerances of fermentation
temperatures/length. This perhaps makes ale homebrewing more challenging (due
to the almost limitless possible variations), but equally easier for the amateur
to produce than lager as fermentation conditions are more flexible and forgiving.