Curbing the brew day?
I am an all-grain brewer and I was thinking of ways to lessen the wrath from my wife over how long it takes to brew. One idea I came up with was to mash and sparge (which takes about two hours) the night before, collect the runoff and store it. Then the next day start my boil and be done with that in two hours. Will I run into any contamination or other problems?
Whenever I am thinking about alternate approaches to brewing methods I usually ask myself if my idea or something akin has been done previously. To me there is comfort in precedence, especially in a craft as old as brewing. Your question does have precedence and an example of splitting wort production into two phases can be seen with malt extracts. But instead of prolonged storage of un-hopped wort you want to just briefly store it before resuming the brew day some eight to 12 hours later.
The biggest concern with wort storage is microbiological. There are bacteria that do grow in wort and lend undesirable flavors. While Lactobacillus may be the first bacterial genus that comes to mind it does not concern me nearly as much as Obesumbacterium proteus. This fat little bugger produces a variety of off-flavors including very potent variants of phenolic, sulfur and fecal aromatics. Not a very pleasant bacterium to have growing in your wort and one that you will certainly remember like your birthday if you ever are confronted by its signature aromas!
The thing to know about wort spoilers is that they grow best at elevated temperatures. Lactobacillus species are anaerobic bacteria that have an optimal growth temperature around 120 °F (49 °C). Obesumbacterium proteus does best in a aerobic environment at 104 °F (40 °C).
If I had all tools at my disposal I would collect wort from the mash in a small buffer tank, pump the wort through a flash pasteurizer equipped with a chiller section and store my cold, pasteurized wort at about 32 °F (0 °C) in a clean and sealed vessel before use. When I was ready to move it to the kettle I would run it through another heat exchanger and heat it up during the transfer to the brew kettle. A variation of this process is used by juice producers who process fruit into so-called “single strength” juice that is pasteurized and aseptically stored before packaging. Many fruit juices are prone to the same spoilage organisms as beer and storing single-strength juice (as opposed to frozen concentrate) for very long time periods is commonly used.
Back to homebrewing reality . . . you certainly do not have a pasteurizer at home equipped with a chiller section and you probably do not have a heat exchanger sitting around that you could use to heat the wort on the way to the kettle. But you do have a brew kettle and (hopefully) a wort chiller. With this equipment you could collect the wort from your mash tun in your kettle and maintain the wort temperature between 180 and 200 °F (82 and 93 °C) during wort collection.
Once you have collected all of your wort, hold the hot wort for between 10–20 minutes and then transfer it to your storage container of choice, using your wort chiller to cool it during transfer. This is a crude form of heat processing and will work to reduce the bacterial population of the wort to delay spoilage. The key is to get the wort as cool as possible. In practice this means chilling to between 70 and 80 °F (21 and 27 °C) with your wort chiller and moving the wort into the refrigerator before use.
So far I have extended the process of wort production by about an hour and I am not done adding time to the brewing process. The next day you wake up and now want to finish the brew. The easiest thing to do at home is to transfer your now cold wort to the brew kettle and kick on the heat. This is going to take some time since the wort is probably around 40 °F. If you could use your wort chiller as a pre-heater you can shave some time off this, but the bottom line is that the heating time is extended. You’ve probably added another hour to the brewing process.
The other thing about this process is that it requires a lot more energy than your current process because you have added another cooling and heating step as a minimum. And if you heat the wort to somewhere around 190 °F (88 °C) during wort collection, as I suggest, you have added heating on the front end. This is certainly not the most efficient method if your goal is simply to hit the pause button on the brewing process for the night.
Unfortunately the brewing process does not have a convenient pause button. You could try to simplify the method above by simply collecting wort in a pot, stuffing it in the fridge and hope for the best. This probably would work most of the time, but when it fails you will have unsalvageable wort.
I did just write a fairly long essay that pretty much concludes with “maybe this is not such a hot idea.” I did answer your question, however, and as a Q&A columnist that is what I do. But I am also allowed to ask questions and I have a question for you: does your wife dislike your long brew days because you take over the kitchen, make a mess and prevent her from cooking the simplest meal or does she dislike the long brew days because they take you out of commission for an entire day of the weekend?
If the kitchen is the issue I suggest moving your setup out of the kitchen! You can mash and sparge somewhere else and use the stove top to heat water if you don’t have a Cajun cooker-type set up. I know, you still have some pots on the stove but at least some of the clutter is out of the way. If time is the issue you may want to consider overnight mashing. Prepare your mash, chuck into an oven set at ~160 °F (71 °C) and then finish up the next day.
Personally I would try to figure out a way to do everything in one day while simultaneously keeping peace with your wife because in all truth you probably have the best shot of brewing the best beer by sticking with the methods that have emerged as the best brewing methods. Good luck!
Brew Your Own Technical Editor Ashton Lewis has been answering homebrew questions as his alter ego Mr. Wizard since 1995. A selection of his Wizard columns have been collected in “The Homebrewer’s Answer Book,” available online at brewyourownstore.com.