What do all of these numbers mean?
One of the most important tools a brewer receives from a maltster is the Certificate of Analysis or COA. The COA lays out lab tested information in a standardized format to help quantify exactly what is going on in the malt and help with any adjustments that may need to happen in the brewing process. We’re breaking down some of the our favorite aspects of a COA, but there are many more to dig into. Let’s start with Color!
SRM
How a beer looks is one of the first sensory inputs for a customer, so it makes sense that the first thing a brewer looks at on a COA is the SRM. SRM or Standard Reference Method is a scale from 1-40+ that helps quantify malt color.
Maltsters use this scale as a part of how they classify malt styles - “Pilsner” or “Pale” or something else entirely. The SRM and style also helps brewers imagine the flavors that the particular malt will add to the beer. Pilsner (1-2) malts are lighter flavors - Hay, Grass, Cracker; while Pale malts (2-4) have darker flavors - Biscuit, Bready, and Bread Crust. All the way up to 40+, which would be a black or highly roasted malt and give off Coffee, Chocolate, and Burnt flavors. There are always overlaps and exceptions, but the SRM of a malt is a good first piece of information to know what you’re working with.
Extract
One of the main things malt contributes to beer is starch that enzymes extract and convert into fermentable and non-fermentable sugars during the mashing process. These sugars act as food for yeast to create alcohol and help create body in beer.
On a COA there are two items related directly to the amount of extract a brewer can expect - Coarse Grind (CG) and Fine Grind (FG). The Fine Grind is the maximum amount of extract our laboratory could get by essentially grinding it to flour. The Coarse Grind is the extract achieved in simulated brewery conditions. Usually a brewer, who knows their system, can expect an extract in the range of these 2 numbers. This helps when planning recipes to dial in how much malt you actually need to use to hit your target sugar extraction!
Protein
Protein is what gets broken down into all of the things a brewer needs to convert the starches in grain to sugars while they are brewing. An ideal Total Protein range for base malts is 9%-12.5%. From that Total Protein, not everything will be soluble into the beer, but the amount that is (Soluble Protein) is used in conjunction with the Total Protein to make the S/T ratio, which informs brewers on how much conversion happened during malting.
The S/T Ratio allows brewers to know if malt is fully modified or not, which helps them adjust their water temperature during the mash process to allow for enzymes to convert the starches properly. The greater the S/T Ratio, the higher the modification of the malt. If the number is too low, a more complex mash regime is required. A target ratio for most standard malts is 35%-55%, typically higher Total Protein leads to less modified malt due to this ratio.
Diastatic Power
The Diastatic Power or DP is a measure of the enzyme activity in the malt. For the starches in malt to be converted to sugars, there needs to be a high enough level of these enzymes, especially when using specialty malts which have lower DP compared to base malts. Using this number in conjunction with mash temperature, brewers are able to provide enough fermentable and non-fermentable sugars to give beer their desired body and alcohol amounts.
For all malt brewing, a proper DP range is 80-115 ºLintner, which will provide enough enzymes to convert base malt in addition to specialty malt, without creating a thin body from over converting sugars.
FAN
FAN or Free Amino Nitrogen, is a measure of amino acids, which are the smallest parts of the proteins. FAN is directly related to yeast health and often thought of as nutrients for the yeast. Most base malts have enough FAN to allow healthy yeast growth, but if you have too much, you can have issues with shelf stability and spoilage in beer. Different yeast strains require different levels of FAN and the less malt you have the less FAN you have for your yeast. Checking both a COA and with your yeast provider for required FAN levels for your strain can help mitigate any issues with yeast performance related to FAN.
We hope this helps you understand more about what exactly is going on with the COA you receive from your malt supplier. If you would like to see a COA for your specific batch, send us a message and we’ll hook you up!