Parti-gyle brewing

What is actually happening

A mash does not give up its sugar evenly. The first liquid drawn off is dense; what follows is progressively thinner. Modern practice blends the whole lot to one target gravity, and parti-gyle does the opposite — each portion becomes its own beer.

That single fact explains a great deal of British brewing history. Families of beer at descending strengths from one brewday, the small beer given to servants and children, and the practice of blending portions back in measured proportions to hit several targets from one mash are all consequences of it.

It is also why historical strength records need reading carefully: a brewery producing a strong ale and a table beer on the same day was frequently not brewing twice.

The technique survives in a few places and as a deliberate revival. It is labour-intensive and it makes the later beers hard to balance, which is why blending won.

Styles where this step is decisive

• Belgian table beer0.5–3.5% ABV

  A very low-strength everyday Belgian beer, historically served with meals including in school canteens.

• British strong ale5.5–8% ABV

  A broad category of strong English ales, malt-led and fruity, sitting between strong bitter and barley wine.

• English barley wine8–12% ABV

  The strongest traditional English ale: dense malt, dried fruit and marmalade, built to be kept for years.

Related steps and concepts

• Lautering — The step it changes.
• Sparging — What it treats as separate runnings rather than one.
• Blending — The alternative use of the same portions.