In all-grain brewing, continuous sparging is the practice of rinsing your grain bed with hot sparge water such that the inflow of water from your hot liquor tank matches the outflow of wort from your lauter tun. Sparge water is added so that the top of the grain bed is always covered with about an inch (2.5 cm) of water, except perhaps near the end of wort collection. Continuous sparging, also called fly sparging, is sometimes seen as too complicated or fiddly — especially compared to simpler techniques like brew in a bag (BIAB) or batch sparging. However, it does not have to be. Here are three fly sparging tips.
Use “Pulsed Sparging”
When I started all-grain brewing, I had a cobbled together system with a “whirlygig” sparge arm. When water ran through the sparge arm, it spun like a lawn sprinkler and sprayed the top of the grain bed with water. Getting the rate of inbound sparge water to equal the outbound rate of wort was something that took constant monitoring. I was constantly adjusting ball valves or hose clamps. What I didn’t realize until later was that getting the two rates to match exactly isn’t the end all be all of fly sparging. As long as you keep some water on top of the grain bed, everything is fine.
So, I started to “pulse sparge,” which is just a name I made up for a common practice in commercial brewing. In pulsed sparging, I’d add a fairly large amount of sparge water to the top of the grain bed, so that the water standing on top was perhaps 2 to 3 inches (5–8 cm) deep, then wait for the water to almost fall to the level of the grain bed, then add another dose. When I did that, I only needed to worry about the sparge water every 5–10 minutes, and I could focus my attention on running off the wort at a reasonably steady rate.
I also came to realize that “sprinkler” type sparge arms, in which small droplets of sparge water fall through the air before hitting the water resulted in these droplets cooling substantially before they hit the mash. Now I try to either simply pour my sparge water in, or use a sparge arm that sits under the water atop the grain bed. That and realizing what temperature my sparge water should be has helped me collect the wort more easily and with better success.
Increase Your Collection Rate
When I first started all-grain brewing, I heard about homebrewers sparging for 90 minutes, or in some cases as long as 2 hours to get the best extract efficiency possible. What experience has taught me is that longer sparges are only slightly more efficient than shorter ones. If you are looking for a place to shorten your all-grain brew day, here is one of the first places to look. I now shoot to collect my wort in about 60 minutes most times I brew, but have rushed things to 45 minutes with no large negative consequences.
Heat Your Wort While You’re Collecting It
After my 90-minute wort collection sessions, I used to then turn on the burner and start heating the wort. It took me way too long to realize I could be heating the wort throughout wort collection. Now I turn on my burner once I’ve got a couple gallons in the kettle. I keep heating and take the temperature of the wort as it heats. I adjust the burner so the wort starts boiling right when I stop collecting wort, or slightly before. If you have a lot of wort to boil off, as in a big beer, you can bring the wort to a boil even earlier (especially if you don’t mind the wort picking up some extra color).
Notice that these last two tips are connected. The faster you run off your wort, the faster you would have to heat the collected wort to get it to a boil at the end of wort collection. One of the reasons I don’t collect my wort in an even shorter amount of time is that I’d then be sitting around twiddling my thumbs waiting the boil to start. I try to heat the wort at a reasonable rate (to not burn excessive and wasteful amounts of propane) and that gives me the minimum time I would ever consider for wort collection. (Heating the wort at a rate 2 °F (~1 °C) per minute, it would take about 30 minutes to go from mash temperatures to boiling.)
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