Why High Gravity Brewing?June 9, 2012 # 5:48 PM # Special Techniques Products # One Comment
High gravity brewing (HGB) refers to specialty brewing process with an increased specific gravity. It is a common practice in many modern breweries round the world. It is seen as so natural way of brewing, that many brewers tend easily to forget the actual reasons, why it has originally been developed. By HGB brewing technique, the wort produced has higher gravity than that of in final beer. The gravity is higher than in sale gravity, but normally not much higher than 17°P.
Why High Gravity Brewing?
1. Energy costs saving; lower brewing size (less wort boiling etc.), less volume to cooling in fermentation and maturation tank.
2. Cleaning costs saving; the cleaning surface smaller than normal gravity brewing
3. Labor costs saving; this cost is correlating to beer volume
4. Increase brewing capacity; because we can produce greater final beer volume with de-brewing techniques and it means normally 20- 30% higher output from a brewery until filtration.
1. Better colloidal stability; because of the reactions between polyphenols and polypeptides in HGB technique is stronger.
2. Lower foam stability; more loss of hydrophobic polypeptides (good foam formation) in boiling process.
3. Lower beer aroma; because of more adjuncts are used and this may be the biggest reason to lower aroma concentrations.
4. Higher fusel alcohol content; cause of higher fermentation temperature
5. Higher alcohol content; HGB beer tends to have higher alcohol content compared to other beers due to the concentration of sugar and flavor-enhancing ingredients at the beginning of the brewing process.
De-Brewing (Blending/Dilution Water)
Water for dilution HGB beer must be high quality water. Mistakes in that easily destroy the beer flavor. Normally water must be treated to reach the correct quality e.g.
- Oxygen content < 0.1 ppm
- Carbon dioxide content > 3 g/L
- Microbiologically pure
- Free of chlorine and chlorophenol
- Potable water quality
- The same beer temperature
High gravity brewing (HGB or blending) is used by some of the big US brewers and now common practice in many modern breweries. Cost savings are obvious, but carefulness is needed in planning the process. Very high gravity may become many problems e.g. yeast’s physiology and its metabolism in those extreme conditions.