Prior to conducting a sparge, the grains must undergo a mash. Mashing is essentially just the soaking of the grains in hot water to activate the enzymes within the malt which subsequently convert the starches into sugars. There are a number of methods for mashing but I will just summarize the aspects of a single temperature infusion mash which is popular for homebrewing:
There are other considerations beyond the three detailed above (e.g., mash pH, sufficient diastatic power,…) but the above are the basics.
At the completion of the mash the liquid is referred to as wort which can be described as sugar water. There are various sugars that result from the mash and an example of the mixes of the sugars in the wort is illustrated below:
After the mash is complete the wort must be separated from the spent grains in a process called lautering. A converted cooler is a popular piece of equipment used by homebrewers to conduct a mash. The cooler is converted for lautering by placing a false bottom, braided hose or a perforated manifold at the bottom of the cooler.
A false bottom could be constructed of plastic or metal and is convex shaped with many holes in it. Think of it as a filter. Below is a photograph of a metal false bottom that could be placed at the bottom of a round cooler:
In contrast a braided hose is something you could obtain from a hardware store (in the plumbing section) or your homebrew store. Below is a photograph of a braided hose:
Manifolds are constructed of copper tubing or PVC pipes which are perforated. Homebrewers typically implement their manifolds in a DIY (Do It Yourself) manner but some can be purchased as well. Below is a photograph of a manifold constructed of PVC pipes and shaped to fit a rectangular cooler:
Which method is used to separate the wort is a personal choice which may be influenced by the type of cooler selected for conducting the mash (e.g., round vs. rectangular).
Should you recirculate (vorlauf) the first running of your mash?
Depending on how well your false bottom/braided hose/manifold separates (e.g., filters) the wort there may be a need to recirculate the first running wort. You do not want any spent grain material getting into the brew kettle and via recirculating the first running wort back into the mash tun the grain bed will operate like a filter bed to catch the spent grains. If the implementation of your system is very good at keeping out spent grain particles there is no need to recirculate (vorlauf) the wort. I personally choose to conduct a vorlauf since it only takes a few minutes and I rationalize that the first running wort that I collect is clearer – a benefit with not much time expended.
Why Sparge your grains?
Once the wort has been separated and collected the remaining spent grain still contains residual sugars. The motivation for conducting a sparge is to get every bit of goodness from those grains so no sugars go to waste. While it is not absolutely necessary to conduct a sparge it has been my consistent experience that most homebrewers tend to be prudent individuals and the tenet of “waste not want not” often comes to mind.
If you over-sparge tannins will be extracted from the grains and this will result in a beer that has astringency (an unwanted quality). A method to manage this situation is to monitor the pH of the sparged wort and stop sparging when the pH raises above 6.
The fly sparge method is where the hot sparge water (e.g.,170 °F) is very slowly sprinkled above the spent grains. The idea is to maintain about 1 inch of water above the grain bed and complete this process over about 45 - 60 minutes. The equipment used to accomplish this sparge is typically a cooler containing hot sparge water (sometimes referred to as the hot liquor tank) which is gravity feed to a sparge arm. The sparge arm could be constructed of a plastic pipe(s) with perforations to permit the slow trickle of hot sparge water. Or another implementation is a circular piece of copper tubing which is perforated with holes (see photo below).
One of the purported benefits of the fly sparge method is that if conducted very slowly you achieve the ultimate in conversion efficiency (i.e., maximum extraction of sugars from the grain). According to the BisonBrew website: “You can expect somewhere in the 80 to 95 percent range for fly sparging efficiency”. For those folks who highly value utilization of their ingredients this may be the preferred method for sparging.
I conduct fly sparging in my home brewery but I conduct what I term an abbreviated fly sparge. Instead of slowly sparging using a sparge arm I manually add sparge water using a measuring cup to my lauter tun. I do this over about 10-15 minutes. While I do not achieve the ultimate in conversion efficiency, I always obtain very good results and the results are consistently repeatable so I achieve my target original gravity.
Brew in a Bag (BIAB) including sparging
A relatively new method for conducting a mash is to just put your grains in a big mesh bag and place that bag in your brew kettle for conducting the mashing process. This method does not require any additional equipment such as a converted cooler and for folks who prefer not to sparge it saves time. It is a fairly simple process other than the need to have the bag held above the brew kettle to drain. I have seen photos where homebrewers construct a winch type system to lift the bag out of the kettle and hold it in place as it drains.
With the BIAB method there is the challenge of maintaining a consistent mash temperature over a mash duration of 60 minutes but some homebrewers will cleverly insulate the brew kettle using blankets (or something similar). They also could periodically apply heat to the kettle over the 60 minutes but then you have the risk of burning/damaging the grain bag if it is touching the bottom of the kettle.
Once the bag has completed draining some homebrewers choose to conduct a sparge afterwards to maximize sugar extraction. They will pour hot sparge water (e.g., 170 °F) on the top of the bag and let the sparged wort drain out. This method is not too dissimilar from my abbreviated fly sparge method except no lauter tun is used.
My guess is that the batch sparge method is the one most used by homebrewers since it is relatively simple and obtains very good conversion efficiency.
Once the mash is complete and the wort completely separated you add the hot sparge water (e.g., 170 °F) to the mash vessel (e.g., converted cooler) and stir the grains/water and let sit for about 10 minutes. Afterwards you just drain the second running wort into the brew kettle. The advantages here is that you do not need any additional equipment (e.g., no additional coolers, no sparge arm) and this sparge method is quicker than the typical fly sparge method. Some homebrewers report that they obtain conversion efficiencies comparable to those who fly sparge. Since there are nuances to how a homebrewer specifically implements their sparge methods I suppose this is possible.
Is there a best method?
It really comes down to what a homebrewer’s priorities are. And while I have detailed the stereotypical methods above each person could tailor a given method to best suit their desires (e.g., my abbreviated fly sparge method).
I am cognizant that some homebrewers simply choose to not conduct a sparge at all and compensate by purchasing more grain to account for a lower conversion efficiency and for them this is the ‘right’ choice. I am somewhere in the middle in that I want to obtain increased extraction of sugars from the spent grains but I am not willing to spend an hour in the fly sparge method so I compromise time vs. optimizing conversion efficiency.
One of the beauties of homebrewing is that we get to brew the beers we like and brew them the way we like. Sparge the way you like!
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