Pitching Wild Yeast, Batch Sparging & Racking: Mr. Wizard
Q Are pitching rates similar or different for “wild” type cultures (Lactobacillus, Brettanomyces, Pediococcus, etc.) to that of typical ale yeast?
Scott Rylie
Via Facebook
A Pitching rates for wild yeast and bacteria are really all over the place.
Brettanomyces species can be used in place of Saccharomyces species for the primary fermentation of wort into beer. Brettanomyces has become a very popular “wild” yeast in certain brewing circles and imparts an interesting aroma and flavor to a wide range of beer styles. When used as the primary yeast strain the flavor contribution is more up front and immediate compared to when Brett is added to beer during aging, where the aroma notes develop slowly over time. If you are looking for numbers, the range in pitching rate varies from about 250,000 cells/mL to over 10 million cells/mL, depending on how the yeast is going to be used.
If you want to use Brett for the first time, I would use it after primary fermentation is complete and add for bottle conditioning. This yeast is a “super-attenuator” and ferments sugars that ale and lager yeast cannot. This means that these beers have the potential to be bottle bombs. Heavy bottles, like champagne bottles, are recommended. Pitch with about 1 million cells per mL to give your beer a good shot of developing the aroma that is expected.
Bacteria, such as Lactobacillus species and Pediococcus species are completely different, for two big reasons. The first thing separating these bugs from yeast is that they are sensitive to hop acids, and in some cases alcohol strength. This means that souring beers that are highly hopped and high in alcohol can be a real challenge. Even moderately hopped beers can give lactic acid bacteria the cold shoulder and will not turn sour. This is really frustrating when you are intentionally trying to do something that many brewers curse when it happens on its own. I have been in that boat!
The other thing about these bacteria that set them apart from yeast is that it does not take many cells to affect change. A few hundred cells/mL in the proper setting can grow into a population large enough to have obvious flavor contributions. In comparison to yeast cell densities, bacterial densities are usually much lower. A lager beer that has been thoroughly spoiled by lactic acid bacteria may have only 5,000 cells/mL of the culprit. The interesting thing about bacteria is that they can grow very well by feeding on amino acids associated with autolyzed yeast cells, especially in anaerobic environments. This means that the bottom of a beer tank is a pretty ideal propagation container for bacteria, and beers often sour when held for prolonged time periods with yeast present.
The take home message here is that the answer to your question depends on what you want to accomplish by adding these sorts of organisms and how quickly you want results. Most beers produced with these types of cultures are not produced overnight and it is very important to be patient.
Q Help me with batch sparging. To get the grain bed to 168 °F (76 °C) you need to heat your sparge water to 180–195 °F (82–91 °C) depending on the volume of grain. I also have read that the mash out isn’t really necessary as the boil stops enzymatic activity. Do you see any problems with only heating my sparge water to 168 °F (76 °C) to eliminate any possible tannin extraction from the hot liquid on the grain?
Russ Brunner
Fort Lauderdale, Florida
A I remember when I first began homebrewing back in 1986 and almost immediately wanted to start brewing all-grain. At that time the information related to homebrewing was a little more difficult to find and my quest for information quickly landed me in the stacks of McKeldin Library on the University of Maryland campus in College Park. There I found a bunch of texts that seemed so confusing to my young mind. Luckily I later found some homebrew books that helped demystify mashing.
The mashing method I cut my teeth on was the “simple” infusion mash. One mash temperature followed by sparging with hot water and onto the kettle wort flowed. Only later did I pay much mind to step mashing and decoction mashing. These days it seems that many homebrewers have thrown out the KISS philosophy and have replaced simplicity with complexity. I suppose I am a hypocrite for taking this view since I actively encourage commercial brewers who are building new brewhouses to invest in equipment permitting temperature profile mashing, but I really don’t believe that there is a compelling argument for most homebrewers to mess around with step mashing.
OK, so now that I have set the stage, onto the answer. You are describing the dilemma of an infusion masher, that’s you, who is peeking over the fence at what step mashers do. Step mashers tend to “mash-off” at the end of the mash before they move their mash to the lauter tun. Infusion mashers go straight from mashing to sparging and skip the mash-off step. So what’s the difference and why?
When mash is stirred in a mash mixer and pumped to a lauter tun it behaves differently than an infusion mash. As it turns out, wort separation is easier when the mash is heated or “mashed-off” before the transfer. This also serves to inactivate enzymes and allows the brewer to control mashing, stop the mash, then get on with wort separation. This is not necessarily a better method from infusion mashing, it’s just different. Most commercially brewed beer in the world uses some sort of stirred mash and lauter tun or mash filter for wort separation. Decoction mashing and the American double-mash used for dealing with solid adjuncts like rice and corn are both variants of stirred mashing.
In the infusion method there is no mash-off and hot sprage water, usually around 168 °F (76 °F), is sprayed directly on the mash bed after mashing. Since infusion mashing usually is conducted at 149–158 °F (60–70 °C), enzyme activity continues as wort flows from the mash tun to the kettle. Even when hot sparge water is sprayed on the mash bed the wort temperature in the kettle is never much hotter than the mash temperature due to heat loss. This method works very, very well and is the traditional method the British use to brew ale.
Discussions of yield improvement may include increasing the sparge temperature of infusion mashes to reduce wort viscosity and eek out as much extract as possible from the grain bed. There has been a lot of research related to tannin/polyphenol extraction associated with high sparge temperatures and some of the studies conducted in the mid-1990s convinced me that high temperature sparging is not the recipe for disaster that many believe. Most of this research also included milling methods, especially hammer milling, that have dramatic improvements on extract yield when combined with modern mash filter technologies. The take home message is that “hot sparging” can be used to produce high quality wort as long as the variables effecting tannin/polyphenol extraction, mainly pH, are controlled during sparging.
In practice, most brewers these days continue to sparge with water that is about 168 °F (76 °C) because it works well and brewers tend to be a fairly traditional lot. The old adage stating “if it ain’t broke, don’t fix it” is alive and well in the modern brewery.
Q What is the best way to move my beer from primary fermenter to secondary without oxidizing or spoiling the beer in anyway without using carbon dioxide?
Grant Geelong
Victoria, Australia
A Fortunately for homebrewers there are convenient ways to move beer around without ruining your homebrewed suds with the ill effects associated with oxygen.
As you mention in your question, one handy method to help reduce oxygen pick-up during racking is by using carbon dioxide as a blanketing gas. While this method is handy, it does require you to actually have bottled carbon dioxide laying around for use. (I will assume that suggesting other blanketing gases like argon and nitrogen are not of interest to you, so I won’t discuss them here.)
The best way in general terms to limit oxygen pick-up during racking and bottling is to fill the beer from the bottom of the container and then to limit the amount of headspace in the container by matching your container size to the amount of beer you have on hand. Using a solid racking tube to deliver beer to the bottom of the container being filled is a simple and reliable method to control turbulence during filling. Once the beer has been racked it is helpful if some carbon dioxide gas is produced by yeast because this will help scrub the headspace of oxygen. Racking with some residual extract is the best way to help this process happen.
Another important consideration is the oxygen barrier properties of the secondary fermenter. While it is acceptable to ferment beer in plastic containers, I would avoid aging beer in a plastic secondary because ordinary plastics allow oxygen to travel across the container wall and into your beer. Not the ideal situation.
The challenge of oxygen pickup pops up again when it is time to move your beer from the secondary to the final container. If the container is a keg you can fill the keg from the bottom using the tube in the keg for filling. But most homebrewers who keg have carbon dioxide containers, and I am guessing that you don’t have this set up. This means that you are most likely bottle conditioning your homebrew and need to rack your beer from the secondary to a bottling bucket, and then into your bottles. This is the step in the brewing process where real damage from oxygen often occurs.
The first challenge is to move the beer from the secondary to the bottling bucket. Unlike the transfer from the primary where some fermentation is happening, the beer at the end of secondary is done fermenting. My advice is to keep the time investment to a minimum. Start by preparing your priming solution and pouring into the bottling bucket, then, fill your bottling bucket with beer using your racking tube and quickly bottle. At home this is the method to use when you do not have pressurized containers.
Commercial brewers do things a bit differently. Even brewers who bottle condition fill their bottles with some level of carbonation in the beer. This allows the beer to be foamed or “fobbed” before the bottle is capped. Fobbing pushes air from the headspace and is a very effective method used to reduce the oxygen content of bottled beer. In order to do this the beer must be stored in a pressurized vessel, such as a keg during storage so that some level of carbon dioxide remains in the beer.
You ask a question with a short and simple answer. The fact is that without using carbon dioxide as a blanket gas and pressurized storage containers for secondary fermentation and/or bottling containers it is difficult to really control oxidation.
