Cold Mash

Discussion in 'Homebrewing' started by minderbender, Oct 1, 2018.

  1. minderbender

    minderbender Initiate (187) Jan 18, 2009 New York

    This month in BYO Magazine (the October issue), Mike Tonsmeire has published an article on brewing "table beers," which he defines in general terms as any beer with an ABV below 3%. (Coincidentally he also just opened his brewery with Scott Janish. Here's the website.) One of the techniques he describes is "cold mashing." It's a bit of a misnomer because it doesn't refer to an actual mash, in which starch is converted to sugar. It's more of a steeping process where the crushed grain is soaked in room-temperature water for several hours. The idea is that the water dissolves a lot of the ingredients that you want to get from malt (flavors, proteins, etc.) but does not dissolve very much of the carbohydrates (Tonsmeire estimates 25% for base malt and 50% for crystal malt). So what you end up with is a solution that is rich in flavor and protein but low in carbohydrates, enabling you to brew a flavorful low-gravity beer. Or, of course, you could use the solution to augment a higher-gravity beer, boosting its flavor, body, and foam without pushing it too far into imperial territory. Either way, the liquid still needs to be brought to mashing temperature and held there for long enough to convert the starches. Once that's accomplished, the wort can be used just like any other wort of a comparable gravity. Tonsmeire mentions in passing that the leftover grain can be used like an adjunct, because it is low in flavor and protein but rich in starch (much like rice or corn).

    Has anyone experimented with this technique? I'm intrigued by the idea of brewing two beers: (1) a low-gravity but malt-forward beer like a porter, and (2) a normal-gravity beer with yeast-driven flavor like a Belgian ale, or perhaps an easy-drinking lager beer, using the grains from the cold mash in place of the sugar or adjuncts that might normally be used. (Obviously in this scenario the dark grains would not be included in the "cold mash" but instead would be steeped separately. Although now that I think about it, I wonder how much color/flavor would be left after the "cold mash.")

    The difficulty is brewing both of those beers on the same day, which would make it a long brew day. But I suspect the grains from the cold mash are susceptible to rapid spoilage, so you'd want to use them pretty quickly. I suppose you could refrigerate them, but that raises its own issues (not least of which, that would take up a lot of space in my refrigerator I think).

    Anyway it's something I hope to play around with and I was wondering if anyone else has tried it.
  2. Genuine

    Genuine Devotee (420) May 7, 2009 Connecticut

    I've been playing around with the notion of doing a "cold sparge" with a gallon of distilled to see if that changes anything in my brewing. I have a 2 Vessel Kettle Rims system and use the full volume. I've been thinking of restricting it by a gallon. I'm wondering if I could do an overnight cold mash, and then bring up to mash temps to finish the next day and continue on with the process. Both of their research has been very intriguing and insightful.
    minderbender likes this.
  3. telejunkie

    telejunkie Aspirant (238) Sep 14, 2007 Vermont

    Never tried it, but was wondering about an overnight cold mash to make a 5-gallon table beer, wake up, sparge that off and proceed with that batch on the side, and use the "spent grains" as part of the mash for a DIPA. which you could load up with oats/rye or you could try to go dry with it more Brut-like. Was definitely an interesting read btw...

    don't mean to derail the topic, but in sad news (at least for me), since Tonsmeire is starting the brewery, he will no longer be writing the Advanced Brewing column in BYO anymore. On a bright note Colin Kaminski is stepping in the role...and definitely looking forward to his writings. Tonsmeire and Janish both saying they're hoping to continue to write got that going for us.
  4. Ten_SeventySix_Brewhouse

    Ten_SeventySix_Brewhouse Initiate (131) Jul 20, 2016 Arizona

    I've got the October issue sitting on my coffee table waiting to be read. I'm now greatly looking forward to this article. Thanks for the heads-up. I may give this method a try this winter once I've reduced my beer supply enough to justify brewing 10 more gallons.
    minderbender likes this.
  5. hopfenunmaltz

    hopfenunmaltz Meyvn (1,386) Jun 8, 2005 Michigan

    Briess did a presentation a few years back at NHC. You get Flavor, enzymes and color out IIRC. They would combine the liquid with a normal mash, and then proceed. The results were very good.
    chavinparty and minderbender like this.
  6. chavinparty

    chavinparty Initiate (120) Jan 4, 2015 New Hampshire

    Definitely going to try this out.
  7. wasatchback

    wasatchback Aspirant (270) Jan 12, 2014 Utah

    How many have done the cold steep/mash when using roasted grains then adding the liquid back at the end of the boil? I feel like I’d read about it but never bothered to try. I’ve added roasted grains to the end of the mash but that’s it. Trying to tackle more dark/roasty beers this fall/winter.
  8. minderbender

    minderbender Initiate (187) Jan 18, 2009 New York

    I've done this once, but it wasn't a situation where I could really gauge the results (it wasn't a recipe I had brewed before, and it wasn't a dark malt I had used before). For what it's worth I didn't get as much character as I wanted out of the dark malt, but that was most likely a calibration issue, not a fundamental problem with the technique.
  9. Ten_SeventySix_Brewhouse

    Ten_SeventySix_Brewhouse Initiate (131) Jul 20, 2016 Arizona

    I did once for an Irish Stout. I cold steeped and poured the slurry over the grain bed after pulling out the basket. (I do a variation of BiaB.) The beer came out dark and with some flavors of the roasted barley, but lacked "bite" for lack of a better word. I'm not sure whether this is due to the technique's reported benefits of reducing bitterness and astringency from darkly roasted grains, or whether it was related to a higher mash pH due to excluding the dark grains from the mash. (This was before I started acidifying my mash in any deliberate way.) I think the beer would have been better if mashed the traditional way.

    With that said, I think it could work well for something like a Black IPA where you want to smooth out the roast character, or a really big, dark beer where the sheer amount of dark malt needs to be tempered somehow. I just think it's important to consider the affect this technique will have on your mash pH and adjust accordingly.
  10. wasatchback

    wasatchback Aspirant (270) Jan 12, 2014 Utah

    Cool thanks for the replies. Wondering if the pH/mineral content of the cold steeping water plays a part as well as the temperature. I’ve seen a few studies of room temp and what seems like 155ish for steeping. Might have to experiment with a few variables in little mini mashes.