Brewing Wheat

-Some tips for homebrewers

Traditional bottle conditioned Hefeweizen can be brewed at home in authentic quality, if you follow some basic rules.

-Flavor and aromas are determined by certain factors:

1. The use of a very unique top fermenting yeast
2. The share of malted wheat is at least 50%
3. High carbonation of 5.5-9 grams / Liter
4. Bitterness is at the limit of perception, 10-15 IBU

Conclusion:

• Don't substitute the yeast by other ale strains. The typical (must have!) aromas are caused by certain fermentation by-products of Weizen yeast: isopentyl (=isoamyl) -acetate (bananas), 4-vinyl guaiacol and 4-vinyl phenol (clove, vanilla).

• In order to maintain this metabolic activities at repeated fermentings, it's necessary to keep the yeast in a young, fresh and vital condition. Using open fermentation this can be achieved by harvesting the yeast floating to the top. The yeast layer after the first 1-2 days, containing cold break and hop resins, is discharged. Furthermore it's good practice to grow the pitching yeast from small amounts.
• The mashing schedule has influence on the formation of precursors. 4-Vinyl guaiacol is formed from ferulic acid by decarboxylation. Ferulic acid in turn is released from malt during mashing and reaches maximum values when resting at 40-45°C (optimum 44°C).
• The enzymes that help to liberate the ferulic acid at these temperatures have a pH-optimum higher than the mash enzymes. So try to stay above pH 5.7 until you reach over 55°C in your mashing-schedule, then add acid malt or lactic acid to aid saccharification.
• Besides low basic bittering a distinct hop aroma is avoided in many cases in order to promote the flavors given by yeast. Usage of Hersbrucker or Tettnanger hops is typical -varieties with very fine and noble, but mild aroma.
• Sufficient carbonation during bottle conditioning is ensured by adding Speise (green, sterile wort) prior to bottling.
• Cold conditioning is to be recommended, particularly to bind high carbonation rates. But make sure to hold room temperature after bottling until pressure has been built up (2-3 bar =28-42 psi / 4-10 days). Final attenuation and reduction of diacetyl has to be reached.
• Don't age that beerstyle! The aromatic components have a short half-life. Flavor and aromas develop best from 2-6 weeks in the bottle. If lagered properly in a cool place then a flavor stability of 2-3 month can be expected.

More details for crafting these characteristics and about the history of Bavarian style wheat can be found in my German book "Bier brauen nach eigenem Geschmack".