AMS

AMS is especially used in the brewing industry as a liquor treatment to provide optimum pH levels throughout the whole brewing process and improve extract yield, wort runoff and the clarity and stability of the finished beer.

Benefits

-Reduces the alkalinity levels of brewing liquor stimulating maximum enzyme activity in the wort enabling optimum pH levels throughout the whole brewing process.
-Improves extract yield and fermentability
-Adds desirable chloride and sulphate ions in suitable proportions
-Improves clarity and stability of the finished product

For more info read our article, water, water everywhere http://www.murphyandson.co.uk/water-water-everywhere/

Principle

The objective of liquor treatment is to convert your water supply into acceptable brewing liquor. Treating your brewing liquor is vitally important. When applied correctly all the steps throughout the brewing process will be at the opti-mum pH. If it is applied incorrectly you will get poor extract and beer that is difficult to clarify.

AMS adjusts liquor alkalinity without the need for boiling by removing unwanted carbonate ions and adding desirable ions, such as chloride and sulphate in the correct ratios, ideal for most beer styles.

Alkalinity

Alkalinity is mainly caused by calcium carbonate and bicarbonate. The alkalinity of your liquor plays a very important role in pH control. It causes high pH values throughout the brewing process. Hydrogen ions are removed from solution, thus wort pH remains high which results in low extract yield; presence of undesirable protein components; worts and beers prone to infection; increased extraction of silicates, polyphenols and tannins during sparge and harsh “after tastes” in the finished beer.

pH

The pH of the liquor will have little effect on the pH of the wort and beer. Alkalinity and calcium are more important in pH control. Once you have established correct levels of these ions it is advisable to follow the guidelines of typical pH measurements in the brewing process. Hand-held pH meters can be purchased from Murphy & Son Ltd.

Rates of Use

Addition rates for AMS are dependant on the levels of alkalinity and other important ions present in your untreated liquor. Raw liquor can have an alkalinity of up to 300 mg/litre. Brewers need to reduce their alkalinity down to a range of 30– 100 ppm (refer to table 1) depending on which beer styles they wish to produce. In some cases raw liquor can already be in that range so no acid treatment is required.

	Bitter	Strong Bitter	Lager (65°C)	Porter	Mild	Wheat	Stout
Calcium	180-220	200-220	120-140	130-160	120-140	180	120-140
Alkalinity	30-50	30-50	30-50	100	100	35	150
Chloride	150-300	200-300	Low	200-300	300	250	300
Sulphate	250-400	300-400	Low	200-300	150	220	100

TABLE 1. TYPICAL LEVELS OF IONS IN BREWING LIQUOR USED TO PRODUCE DIFFERENT TYPES OF BEER
(ALL FIGURES ARE IN MILLIGRAMS PER LITRE COMMONLY KNOWN AS PPM)

Levels of the relevant ions present in your liquor can be obtained from your Local Water Authority or you can send in 500ml of your raw liquor to Murphy’s laboratory for a full analysis and suggested treatment rates. This service is free of charge once a year.

Please note, Local Authority reports can provide results that are not up to date and may affect your calculations for ideal dosage rates. It is advisable to check the analysis of your water at least once a year, or on a more regular basis if the supply changes.

Another method of working out your alkalinity on a more regular basis, is to purchase alkalinity testing kits which Murphy & Son Ltd are able to supply.

Once you have obtained your analysis of your raw liquor you can then calculate your dosage rates by selecting which beer type you wish to brew and refer to table 1, this will help you determine how many ions to add or reduce.

ALL water used for brewing should be checked for suitability for beer style according to table 1. This includes any water that is used from the liquor tank, sparge or breakdown liquor.

35ml of AMS per hl of this water reduces the alkalinity by 64 mg/litre (ppm) and increases chloride levels by 22.5 mg/litre (ppm) and sulphate levels by 31 mg/litre (ppm).

Knowing this information you can calculate the amount of AMS needed to reduce your alkalinity to the ideal level. This also helps you to monitor how much sulphate and chloride you have added.

This addition of chlorine and sulphate ions has to be considered when adding other salts to the grist.