Cold Steeping Specialty Grains
Steeping specialty grains is a common practice for many homebrewers, particularly those who brew extract or partial-mash recipes. As with many things in the beer brewing process, there are trade-offs to be made in time, labor, extract efficiency, flavor, color, body and foam when we compare one approach of brewing with specialty grains to another. Cold steeping specialty grains is no exception. There are some significant benefits to be gained in reduced astringency, increased flavor, color, and aroma, when using a cold-steeping process. However, there can also be a trade-off in extract efficiency. This can be compensated for by using a greater amount of specialty grains in the steeping process, segregating which specialty grains will go in the mash (or partial-mash) and which ones will be steeped in cold water, or by adding other adjuncts or malt extracts to make up any shortfall in original gravity.
The currently popular process of cold-brewing coffee provides an interesting parallel to cold-steeping specialty grains. Cold-brewed coffee results in a less acidic, smoother flavored, and potentially more caffeinated drink, at the expense of reduced efficiency of the amount of beverage produced from the amount of ground coffee beans used. The main benefit to cold steeping specialty grains is to reduce the astringency extracted from the husks of dark roasted barley or barley malt in the main or partial mash. Astringency occurs when the grains are held in water at higher temperatures than typical cold tap water. Astringency is the off-flavor resulting primarily from tannins, which are naturally occurring polyphenols found in grain husks. This is why some dark roasted specialty grains are offered in dehusked versions, to reduce the extraction of tannins in a typical mash while preserving the dark color and roast flavors in the wort. In a typical beer, the majority of the tannins present are derived from grain husks rather than hops, so addressing the reduction of tannin extraction from malt and specialty grain husks is important in limiting astringency in nearly every style of beer. So no matter what style of beer you are brewing, this reduction in astringency is precisely the point of pursuing cold steeping in your own brewing process.
Tannin extraction from grain husks (particularly dark roasted grains) is directly proportional to the time, temperature, pH, and the volume of water that the specialty grains are exposed to before they end up in the final wort. With that in mind, a long steep in a large volume of hot water at a high pH would extract the most tannins from grain husks and produce the greatest potential astringency. This scenario is often the tactic used for steeping a small amount of specialty grain in a few gallons of water as it is heated before adding malt extract to the water when brewing an extract kit that includes those specialty grains. Also, consider a typical mash where specialty grains are held in relatively hot water for an extended period of time, and we can see that there is a significant opportunity for tannin extraction from grain husks in either extract plus specialty grains, or all-grain brewing. Cold steeping dark specialty grains greatly reduces the temperature of the water that they are exposed to and thus the potential to extract tannins from those grains. Now that we have a handle on how astringency can happen, let’s take a look at the particulars of the cold steeping process to see how we can make it work to our advantage in making better beer.
Since darker roasted grains have the greatest proportion of husk polyphenols and thus potential for extraction of tannins, it would make sense to cold steep dark specialty grains such as black patent malt, chocolate malt, Carafa® malts, or roasted barley, to minimize the potential for astringency. Since these dark roasted grains do not contribute significant amounts of fermentable sugars when included in a mash, there is no particular reason to mash them at typical starch conversion temperatures of 148 to 158 °F (64.5-70 °C) in order to get the flavor and color we want from them. If you are a frugal brewer like me, you can include the not-so-dark specialty malts (Vienna, Munich, caramel, biscuit, etc.) that can contribute fermentable sugars in your mash instead of cold steeping them. As long as you take the usual precautions of sparging with water at a temperature of 168 °F (75.5 °C) that has been adjusted to a pH between 5.7–6.5, and cease collecting wort at a specific gravity of about 1.008, tannin extraction can be kept to a minimum. In this way, you can derive the most sugar from the grains in your mash while minimizing astringency.
By segregating the dark grains in a cold steep, we can reap the flavor and color contributions they offer while minimizing potential astringency. If you choose to cold steep your lighter kilned grains together with the dark grains anyway, you can expect a sugar extract efficiency of between 25% from pale malts or 50% from any crystal malts. Crystal malts provide greater extract when steeped because they have already been “stewed” to achieve a greater degree of starch conversion to sugar within the kernel during the malting process. With that said, you can choose to increase the amount of the lightly kilned malts in a cold steep to compensate for the reduced efficiency or make up the difference in gravity points with more liquid or dried malt extract.
Cold steeping specialty grains can be accomplished in a variety of ways depending on the time and equipment you have available. The grains can be simply steeped in cold water, steeped in cold water with agitation, or in a virtual vorlauf by repeatedly recirculating cold water through the grains. Each method has its advantages and disadvantages, but each still requires a bit of advanced planning and basic brewing or kitchen equipment.
Simply cold steeping specialty grains can be accomplished by crushing the grains as you would for a typical mash and then steeping them at a ratio of 2 quarts (~2 L) water to 1 pound (0.45 kg) grain for 8 to 24 hours at cold (38 °F or 3 °C) to room (75 °F or 23.8 °C) temperature. At this water to grain ratio, dark roasted grains will typically acidify most tap water to near pH 6 that will naturally limit tannin extraction. If your tap water has an unusually high pH and is highly buffered by carbonates (hardness), it may be beneficial to acidify the grain/water mixture pH with lactic acid, a drop at a time and stirred, to get the mixture to near pH 6. A mixture with a pH greater than 6 will lead to tannin extraction and defeat the purpose of cold steeping the grains to diminish astringency.
With a little extra effort, you can speed up the process by following the same procedure as mentioned earlier for regular cold steeping, except to continuously but gently agitate the vessel and its contents for one hour. This could be accomplished by manually rocking or swirling a sealed bucket while watching your favorite sports team on TV, or any number of other imaginative systems or devices you may come up with to keep the mixture moving.
The third method for cold steeping is to implement a virtual vorlauf by placing the grains and water mixture in a mash tun equipped above a perforated false bottom and recirculating the liquid for about an hour, by drawing liquid from the bottom and pouring it back on top, or with the aid of a pump. This approach would simultaneously filter the resulting liquid, eliminating the need to separate grains and liquid with a screen or filter later on.
If you simply steeped the grains, you will need to separate the grains from the water with a fine screen or filter (layered cheesecloth, coffee filter, etc.) before adding the liquid to the rest of the wort in your brewing process. If you chose to recirculate using the virtual vorlauf method, the liquid should be fairly clear as is and most likely will not need additional filtration.
The liquid portion of the specialty grain steep can be added to your brewing process at any time, from wort collection to packaging, depending upon the flavor and aroma impact you wish to have on the finished beer. If the steep solution is added after the wort has been chilled, you run a risk of contamination by wild yeast or other microbes unless the cold-steeped solution is pasteurized by heating it to at least 145 °F (63 °C) for 30 minutes or 160 °F (71 °C) for several seconds. This can be worth the extra effort, particularly if you wish to experiment with how the steeped solution will affect beer flavor and aroma when added post-fermentation. Perhaps the simplest option is to add the solution near the end of the wort boil where it will experience a temperature over 160 °F (71 °C) to sanitize it prior to fermentation without driving off an appreciable amount of dark roast aromas. The potential for experimentation is extensive as to when the specialty grain cold-steep solution can be added in total, or in stages, to your homebrew recipe so take good notes.
For dark beers, where astringency is of particular concern, cold-steeping dark specialty grains can be an alternative to using dehusked grains or in cases where the specialty grains you wish to include in your brew are not available in a dehusked form. Beer styles such as dark European lagers, black India pale ale (IPA), oatmeal stout, or other dark beers where a smoother, less astringent flavor is desired are great candidates to experiment with the cold steeping process of dark specialty grains.
Cold steeping specialty grains also extracts a good portion of the proteins from the grains that contribute to head retention and mouthfeel. This can be used to great advantage when brewing lighter, lower alcohol beer that may typically be lacking in body and quality of foam. When brewing stronger beers, cold-steeping specialty grains can extract more malt flavor from those specialty grains without extracting sugars that are characteristically more complex and less fermentable. This can be used to your advantage if you desire a beer with a drier finish yet full flavor by using more fermentable sugars from adjuncts or pale malt mashed at cooler temperatures. This can provide big flavors with a clean finish for dark lagers or black IPAs.
Another point of consideration for frugal brewers who like to brew all malt strong ales is that since cold steeping specialty grains primarily pulls the color, flavor and FAN (free-amino nitrogen) from the grains, much of the convertible starch remains in the grain. Therefore, cold steeped grains can be added to a conventional mash to yield sugars contributing toward original gravity of another wort. The “recycled” specialty grains from a cold steep process would not contribute much color or flavor, but would still boost original gravity of the wort.
If dark beers are part of your repertoire, or if you shy away from dark beers because they are not as smooth as you would like, try cold steeping. With a preparation and experimentation, cold steeping dark grains may make your transition to “The Dark Side” a little bit smoother.
Bonnie Brown Ale
(5 gallons/19 L, all-grain)
OG = 1.053 FG = 1.014
IBU = 24 SRM = 26 ABV = 5.2%
Ingredients
7.5 lbs. (3.4 kg) American or British 2-row pale malt
1 lb. (0.45 kg) Munich malt
1 lb. (0.45 kg) wheat malt
8 oz. (227 g) crystal malt (15 °L)
10 oz. (283 g) chocolate malt
8 oz. (227 g) coffee malt
9 AAU Goldings hops (30 min.)
(2 oz./57 g at 4.5% alpha acids)
Safale S-04 or other British ale yeast
5 oz. (143 g) corn sugar (if priming)
Step by Step
Steep crushed chocolate and coffee malts in 2.25 quarts (2.1 L) water at cold (38 °F/3 °C) to room (75 °F/ 23.8 °C) temperature for 8 to 24 hours. Filter the mixture through a coffee filter (paper or fine screen) and reserve the liquid to be added at flameout. Single infusion mash the remaining malt. Mix the crushed pale, Munich, wheat, and crystal malts with 3.6 gallons (13.6 L) of water to stabilize the mash at 154 °F (68 °C) and hold for at least 60 minutes. Sparge with 3.6 gallons (13.6 L) of 170 °F (77 °C) water adjusted to pH 5.7 to 6.5. Collect 5.4 gallons (20.4 L) of wort, top up with water to 6 gallons (22.7 L) and conduct a 60-minute boil. Add the hops with 30 minutes remaining in the boil. At the end of the boil, you should have 5 gallons (19 L) in your kettle. Remember to add your cold steeped dark malts liquor to the wort! After the boil, stir the wort to create a whirlpool, then let the wort settle for 30 minutes prior to chilling. Cool the wort to 70 °F (21 °C), aerate well and pitch the yeast. After seven days, rack to secondary fermenter. When fermentation is complete and beer has cleared, bottle or keg as usual.
Bonnie Brown Ale
(5 gallons/19 L, extract with grains)
OG = 1.053 FG = 1.014
IBU = 24 SRM = 26 ABV = 5.2%
Ingredients
3 lbs. (3.4 kg) extra light dried malt extract
1.5 lb. (0.68 kg) Munich liquid malt extract
1 lb. (0.45 kg) wheat dried malt extract
8 oz. (227 g) crystal malt (15 °L)
10 oz. (283 g) chocolate malt
8 oz. (227 g) coffee malt
9 AAU Goldings hops (30 min.)
(2 oz./57 g at 4.5% alpha acids)
Safale S-04 or other British ale yeast
5 oz. (143 g) corn sugar (if priming)
Step by Step
Steep crushed chocolate and coffee malts in 2.25 quarts (2.1 L) water at cold (38 °F/3 °C) to room (75 °F/ 23.8 °C) temperature for 8 to 24 hours. Filter the mixture through a coffee filter (paper or fine screen) and reserve the liquid to be added at flameout. Place the crushed crystal malt a muslin bag and submerge in 5.4 gallons (20.4 L) of water at 160 °F (71 °C). Steep grains for 20 minutes, then remove the grain bag, allowing the liquid to drip back into the pot. Stir in all the malt extracts, then top up with water to 6 gallons (22.7 L) and conduct a 60 minute boil. Add the hops with 30 minutes remaining in the boil. Add the cold steeped liquid at flameout. Now follow the remainder of all-grain recipe.
