Sparging
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Lautering may be followed by rinsing the grains with additional brewing liquor to obtain more extract. This is called sparging, and is a method to increase efficiency. Sparging is entirely optional for home brewers.
Lautering leaves residual extract in the grains. Efficiency can be increased by using more sparge water. However, increased sparge water can potentially lower beer quality.[1] In official, polyphenols may be extracted, along with silicates and other astringent materials That also contribute to beer staling and haze. The traditional rule is to use approximately the same amount of water in the sparge as used in the mash.
In modern practice, the focus had turned to the pH of the wort collected from the sparge because high pH is associated with increased extraction of undesirable compounds. High temperature will also increase the extraction of undesirable compounds, with the critical temperature being around 77°C. This the best results (particularly when fly sparging) are obtained by sparging no higher than 76°C and with very low salinity water (<25 ppm as CaCO3).
The thin wort resulting from the sparge process is called "sparge liquor".
- No sparge
- Batch sparge
- Fly sparge
With fly sparging, more and more unwanted substances from the spent grain go into solution towards the end of sparging. In addition to minerals such as silicic acid (SiO2) and polyphenols, long chain fatty acids in particular play a significant role in decreasing flavor stability. Cloudy wort is especially detrimental nearer the end of fly sparging because it contains a disproportionately high level of long-chain fatty acids and oxidized lipid products, which deteriorate the flavor and flavor stability.[2]
At the beginning of the sparge, the mash pH should be at the target, and buffering conditions should be at full strength. With a fly sparge process, the sugars and buffers are rinsed away and the pH shifts toward the pH of the sparring water (especially if it contains buffering systems such as bicarbonate). If the sparging water is alkaline, the mash pH will rise, and the extraction of tannins, silicates, and ash from the malt husks is more likely add it approaches a pH of 5.8, or when the specific gravity falls below 1.008. The best solution is to use RO water for sparging (with or without added minerals, but definitely no basic salts), or to neutralize alkalinity from tap water.[3] Higher pH of last runnings, around 5.8, result in lower quality beer with respect to astringency, harshness, and general taste, according to experiments conducted with a trained tasting panel.
Acidification of sparge water to the typical mash pH is best for calcium retention.[3]
When the "first worts" have been collected and the mash has settled, but before the surface of the grains has become dry, sparging begins, the hot water (usually at about 78°C, 172.4°F) being sprinkled on from the rotating sparge arms. The sparging rate matches the rate of wort run off, and the liquor displaces the wort downward and through the plates and leaches extract from the grist particles. The high temperature facilitates extract recovery because it reduces the viscosity of the wort and so facilitates run off and it accelerates the leaching of extract from the grist.[4] At higher pH values more tannins and undesirable materials are extracted, leading to reductions in beer quality.
Polyphenol extraction can be controlled by sparging with acidified water.[5]
Sparging disporportionally increases the amount aldehydes extracted, even with low-oxygen methods.[6]
Extract recovered at the end of sparging is not simply diluted (quality) first wort. Last runnings contain little of interest to brewers making quality beer. Although large breweries have financial interest in collecting last worts as low as 1.003, craft brewers rarely collect below 1.010.[7]
To avoid excess oxygen, maintain a layer of liquid over the grain bed when sparging.[8]
When sparging, a rise in pH will increase the extraction of color, astringent bitter substances, and silica from the grains.[9]
References[edit]
- ↑ Fix G. Principles of Brewing Science. 2nd ed. Brewers Publications; 1999.
- ↑ Kunze W. Wort production. In: Hendel O, ed. Technology Brewing & Malting. 6th ed. VBL Berlin; 2019.
- ↑ a b Palmer J, Kaminski C. Water: A Comprehensive Guide for Brewers. Brewers Publications; 2013.
- ↑ Briggs DE, Boulton CA, Brookes PA, Stevens R. Brewing Science and Practice. Woodhead Publishing Limited and CRC Press LLC; 2004.
- ↑ De Rouck G, Jaskula-Goiris B, De Causmaecker B, et al. The impact of wort production on the flavour quality and stability of pale lager beer. BrewingScience. 2013;66(1/2):1–11.
- ↑ Ditrych M, Filipowska W, De Rouck G, et al. Investigating the evolution of free staling aldehydes throughout the wort production process. BrewingScience. 2019;72(Jan/Feb):10–17.
- ↑ Kallmeyer M. To mash or not to mash Kurz/Hoch. Drayman's Brewery website. 2016. Accessed online March 2024.
- ↑ Piper D, Jennings S, Zollo T. Pro-tips on lager decoction mashing, infusion mashing, yeast handling & sauergut (video). YouTube. Published 2022. Accessed 2024.
- ↑ Comrie AA. Brewing liquor—a review. J Inst Brew. 1967;73(4):335–346.