Spent Grains

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Also called Brewers Grains or Distillers Grains.

Spent Grains are the byproduct from malt, husks, and adjuncts after all the sugars, proteins, and nutrients have been extracted in the brewing process of Beer called Mashing.

Spent grains have many agricultural and commerical uses.

1. Feeds
2. Compost
3. Biomass
3. Bread making

Wet spent grains can easily spoil and best used fresh or dried out either through sun drying or kiln drying.

For longer storage, it may be ensiled in an airtight trench silo, or in tightly tied plastic bag silage.

1. Feeds

Brewer’s spent grain is very valuable as a potential supplementary feed for livestock.

It is a safe feed when it is used fresh or properly stored. This is a bulky feed but is a relatively good source of energy and protein.

In general, it was found that spent grain consisted of:

-Protein: 20 – 30%
-Fiber: 20 – 70%
-A notable amount of free fatty acids.
-Decreased total carbohydrates.
-Good levels of iron, magnesium, manganese, selenium, phosphorus (below 5%).

Spent grain is a balanced feed livestock, especially for dairy cows where it can stimulate milk production.

Spent grain can be given in large amounts to dairy cows, up to 15 kg per head daily. A supplement of 8 – 10 kg of wet spent grain is usually adequate to cover the frequent nitrogen deficiency of cows grazing grass only pastures, and can sustain production levels of 4 to 6 litres of milk. Calves can be fed 2 – 4 kg daily.

Spent Grains also have a lot of Fiber which helps slow down digestion and thereby absorb more nutrients.

Wet spent grain can be ensiled alone or in association with other feeding ingredients, for example, with 2 -3 % molasses ( to ensure proper fermentation ), chopped banana by-products ( pseudostems, fruit, skin); chopped root vegetables or leaves.

Spent Grains can also be used as supplementary feed for Bird Flocks.

2. Compost

What livestock doesn’t eat can be composted and turn into soil.

Spent brewery grain could be classified as a nitrogenous waste (fresh = green matter) on the same level as grass clippings.

This means that they compost hot and will do best when layered with some carbonaceous waste (dry = brown matter) such as leaf matter or straw. A good rule of thumb here is to use a 2:1 ratio of green matter to brown matter.

Too much green waste — especially where wet grain is concerned — will likely create a very ripe spoiling mess. If this is of concern or you find the smell too strong add more brown matter. This will slow decomposition a bit, but should also cut down on the smell.

One of the easiest ways to use spent grain as compost is to put it right in the ground. You can did a small ditch between vegetable rows or in flower beds, fill it half way with spent grain and cover it with dirt. In this way the microbes already in the garden can easily do their work on the newly arrived nutrients.

3. Biomass fuel

Dried Spent Grains can also be used as an organic fuel for Gasifiers/Pyrolizers that direct heat to Steam Boilers. Such technologies can be used to power the very same breweries where the Spent Grains came from.

4. Baking

Fresh Wet or Dried Spent Grains can also be used in cooking and more popularly in Baking.

Spent grain can be used in your own cooking and baking too. The Spent Grain can either be used wet (usually after as much liquid has been pressed out of the grain as possible) or it can be dried and ground into flour. Do a little internet searching and you will easily find tons of spent grain recipes for bread, crusts, and plenty of baked sweets like cookies and brownies.

Wet spent grain can be used in low quantities in bread and other baked goods to add flavor and texture.

The study from the University of Bucharest specifically addresses baking with spent grain. In the study they bake bread with 5%, 10%, 15%, and 20% of flour milled from spent grain and then chart the changing nutritive value. What they found was that as little as 5% spent grain flour doubled the breads fiber content, increased the protein by as much as 88%, decreased the carbohydrates, increased the fatty acids, decreased the calories, and increased some of the mineral content.

In short, the brewer’s grain increased the nutrient density of the bread.

One needs to realize that as you increase the percentage of Spent Grain flour, more of the brewing flavors will become apparent. Most studies have found that around 10% SBG flour in a

recipe is the upper limit if what most of the participants enjoyed. But, of course the cocktail of volatiles are going to change with each different batch of beer. You may find you like a really high percentage of spent grain flour from a certain beer style.

5. Grow Mushrooms:

Another interesting use of spent grain is as part of the substrate used to grow edible mushrooms. Because of the spent grains high nitrogen content it is necessary to mix in some sort of carbonaceous matter (much like composting) such as straw or wood chips (a ratio of 1 part grain to 4 or 5 parts straw works well).

Much like brewing, it is very important to sanitize your materials to keep “bad” organisms at bay. To do this you would heat the mixed substrate in a large pot of water (your brewing kettlewill probably work great here, especially if you have a false bottom and spigot on it). So, heat the water (substrate submerged) to about 160°F then put a lid on, turn off the burner, and let it sit for 45 minutes to an hour.

Drain the water and let the substrate become cool to the touch. Once cool, inoculate it with mushroom spores (Oyster mushrooms are one of the most common grown this way), and pack it into a container of some sort (also sterilized).

This could be a plastic bucket, large plastic bags, a metal bucket, or even a wooden crate. Whatever you use, holes will have to be punched or drilled in it to allow the mushroom spores “windows” to grow from (check out some pictures online and you’ll see what I mean).

Once the container is packed with the inoculated substrate it is important to put it in the right environment. The area you keep your growing mushrooms should be somewhere between 70 and 90°F. Maintain a slightly damp moisture level and a slightly higher humidity by putting the container in an enclosed space (tenting plastic sheeting over and around the container can accomplish this easily.

Different mushrooms grow best in different substrates, conditions, and some take longer than others to grow. The basics are all here but if you really want to give mushroom cultivation a serious go, do a little research on the internet and — just like in brewing — don’t be afraid to experiment. Just be sure you are actually growing EDIBLE mushrooms.

6. Dog Treats:

You can use your spent grain as filler for homemade dog treats as well, but please be aware
that hops are very toxic to dogs, so never use spent grains that have come in contact with hops. You can find all kinds of spent grain dog treat recipes online, but try to avoid recipes that use soy or wheat and don’t make your treats out of the grain from wheat ale. Barley and oats are more digestible for dogs.

Spent brewers grain can be a valuable resource. If you find you cannot use your spent grain
in any of the ways listed above and you are brewing regularly it might be worth while putting feelers out into you community to find others out there that might be able to benefit from your beer baking endeavors.

Local farmers or gardeners would likely be happy to take spent grain off your hands. You could make a batch of dog treats for a friend that has a dog if you don’t own one yourself. Maybe you have a family member that loves baking and would be thrilled to get some spent grain flour.
If you try, I guarantee you will find something better to do with your spent grain then simply throwing it away.



http://www.fao.org/ag/againfo/themes/documents/PUB6/P621.htm https://learn.kegerator.com/using-spent-grain/

Last modified: Jun 25, 2019

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