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Happy Feet
10/20/07 06:21 PM  
13 hour mash
The past two days I made a pilsner. I say the past two because I started the mash at 10:00 p.m. and let it sit until 9:30 a.m. the next day before sparging. I was reading a thread, not sure which one, that did this, so thought I would give it a try. Simple recipe, 24 lbs two row, 8 oz Belgium biscuit malt and 8 oz acidified German malt. All went well, the extraction rate was much higher then I was expecting. I also liked the fact I was able to shave 3 hours off my brew day, as well as getting more sugar from the malt. The question is: What are the pitfalls of having the mash sit for over 12 hours? I mash in a cooler. The mash started at 157 and when I got back to it in the morning it was at 147, wrapped the whole thing in a sleeping bag to retain the heat. It all smelled great going into the fermenter. One thought was DMS, but did not detect at this stage. What do you all think?
10/20/07 06:22 PM  
Re: 13 hour mash
First thought that pops into my head is acidulation.

10/20/07 08:05 PM  
Re: 13 hour mash
I've heard that tannins can be extracted out of the grain husks if mashing is carried out very long.
10/21/07 01:33 PM  
Re: 13 hour mash
I think DMS is formed in the kettle at high temperature. Even if it forms in the mash then it will be driven off during the boil because it is volitile. DMS is usually only a problem because it continues to be created after flame out but before the temperature is dropped far enough to stop the DMS forming reaction.
10/22/07 07:19 AM  
Re: 13 hour mash
Chris Firey of the Manayunk Brewery was telling me a couple weeks ago that another local brewpub actually occasionally mashes over the weekend...as in, mash-in Friday evening, sparge on Monday. This procedure is apparently used for sour beers. I'm trying to find out some more.
Dave I
10/22/07 12:34 PM  
Re: 13 hour mash
<<I've heard that tannins can be extracted out of the grain husks if mashing is carried out very long.>>

I'd be surprised. A lot or people, including (I believe, going from memory) the founder or Rogue, have done overnight mashes. No problem except thinner beer, which is easily accounted for. As long as your temp is above bacteria-comfort levels. I have never tried it, but lots have, successfully at that.

<<another local brewpub actually occasionally mashes over the weekend...as in, mash-in Friday evening, sparge on Monday. This procedure is apparently used for sour beers.>>

That's interesting. Please post more if you find anything else out.


10/22/07 01:02 PM  
Re: 13 hour mash
<<<<another local brewpub actually occasionally mashes over the weekend...as in, mash-in Friday evening, sparge on Monday. This procedure is apparently used for sour beers.>>>>

See comment above about acidulation. These long term mashes are what can become "sour mash" and facilitate bacterial growth. Though honestly others on this board are far more capable of commenting on this than am I.

Happy Feet
10/22/07 08:10 PM  
Re: 13 hour mash
Has been fermentng for 3 days now, used a Czech Lager yeast. All smells fine. Will keep you posted on final gravity and tasting notes. If this is successful, will try again. Three hours shorter brew day does take some presure of the day.
10/22/07 08:16 PM  
Re: 13 hour mash
I thought you were talking about a turbid mash or "dreimaischverfahren" gone terribly wrong. The most that has taken me, worst case scenario, is about 6 hours.

Ross Lunato
10/22/07 09:19 PM  
Re: 13 hour mash
From BYO;

Dear Mr. Wizard,

I have been brewing for almost 30 years. To increase mash efficiency, I mash overnight. I do this with beers of low to average original gravities, but especially with high-gravity beers. I will start the mash at 155160 F (6871 C) around 11 p.m. and sparge in the morning around 9 a.m. By then, the temperature of the mash is around 145 F (63 C). I have found this method to be successful at conversion and the beers have been good. Is there any reason why I should not be doing this? I am often asked for brewing recommendations and I want to recommend this, but I need to know if I am wrong.

Trev Cox

Reading, Pennsylvania

Mr. Wizard replies: I am a great fan of methods that make things easier and this method is certainly a time-saver when it comes to scheduling those precious weekend hours. To me, saving time is the best way to improve efficiency. Very long mashes also will improve the extraction of wort-soluble solids from malt and improve your mash efficiency, although mash efficiency is primarily a function of milling and wort separation techniques. I toured a small brewery in California that brewed a batch of stout, then mashed in the second batch and returned the next morning to finish the batch. There are no major problems with this method, but there are a few things to keep in mind to avoid potential problems.

Mashing is all about enzymes. The two key enzymes in mashing are alpha-amylase and beta-amylase. Beta-amylase produces maltose from starch and is most active between 140149 F (6065 C). The thing about beta-amylase is that it stops working when it runs into a branch in the starch molecule. Thats where alpha-amylase comes to the rescue. Alpha-amylase randomly reduces big starch molecules into smaller pieces. Its temperature optimum is right around 158 F (70 C).

When enzymes run out of their substrate starch, in the case of amylases the reactions just stop. No big deal. Brewers typically stop mashing when the mash is complete because they want to efficiently utilize their brewing equipment. In your case, the mash is over at midnight and you are more concerned about utilizing your bed than your mash-tun so you let the mash wait for you to awaken.

The key to your method is keeping your temperature high. If you used this very long mashing method with a low mash temperature, say around 140145 F (6365 C), the result would be very fermentable wort because this temperature range is ideal for beta-amylase activity and also is high enough to get some alpha-amylase activity. When these two enzymes work together, the result is an increase in wort fermentability.

Dry beers and light beers typically begin with this sort of wort. If you want to brew something like Michelob Ultra, a very long mash in this temperature range is the ticket! Just make sure that you achieve complete conversion by using the iodine test before sparging. If you get a black iodine test result, you should heat the mash up to 158 F (70 C) for about 20 minutes for complete conversion. Most homebrewers dont want to brew super-dry beers and should keep the temperature above 150 F (66 C) for the mash.

Keeping the temperature high is also critical for pest control! Wort bacteria dont mess around and will quickly begin growing if the wort temperature falls into the 120 F (49 C) range. Malt is chock-full of bacteria that cause souring of wort, such as Lactobacillus and other bacteria that can lead to some really rank off-flavors. In fact, the most common application to overnight mashing is for sour mashes where the temperature is intentionally allowed to drop into the realm of these bugs that so effectively turn mash sour. Perhaps the best method to guarantee that the mash stays in the 150 F (60 C) range is to put the mash into an oven set at its lowest temperature. I strongly suggest you verify that the lowest temperature is not too hot for the mash before chucking your mash into your oven for a 10-hour bake! However, it sounds like you have a very well-insulated mash tun if the mash only drops 10 F (5 C) over 10 hours.

As long as the mash temperature is adjusted to address concerns about overly-fermentable wort and bacterial spoilage, your method is a real daylight time saver!

Happy Feet
10/23/07 01:01 AM  
Re: 13 hour mash
Ross, thanks for the information! As I said I thought I read this before, and do remember reading this. In my case I had the mash set at 157 and came back to it at 147, to high for a sour mash. The extraction was great. I agree with Trev Cox of Pen. It makes the brew day shorter. Now, when I make a saison or wit beer I do want some acid bite in the finished beer. I always relied on the yeast for this. If you let the mash drop down in temperature, wonder what that would do to the finished beer? Sour might be different from the lactic tang of a good Belgium yeast? Worth the experiment?
10/24/07 11:07 AM  
Re: 13 hour mash
I have seen a lot of Berliner Weisse recipes that call for a sour mash. I'm sure the sourness is based on mash length. So maybe a shorter sour mash could give you the tartness you seek, versus an all out sourness.

I plan to do a sour mash in the near future. Making a Kentucky Common - Sour mash dark cream ale!

Happy Feet
10/28/07 12:52 PM  
Re: 13 hour mash
I racked the lager yesterday. I fermented for 7 days at about 58 to 60 deg. It strated at 1052 and ended at 1006. Smells and taste fine at this point. Now in my beer fridge for a month at 30 deg. No DMS and taste is not astringent at this point. 13 hour mash does make a highly fermentable wort!
Happy Feet
11/25/07 05:29 PM  
Re: 13 hour mash
I racked the pilsner into a keg and forced carbonated to a medium level. Let it sit for 4 days back in the fridge and have been sampling with friends. First of all, it has the characteristics described for Czech lager yeast dry, but malty finish. Its bang on. I do agree with a few posted about the beer being thinner. I think this could be fixed with an addition of dextrin malt or crystal malts for a darker beer. The only other problem I noticed was the beer has a more pronounced chill haze then most of my brews. I will be trying the overnight mash again.

Cheers, and Go Riders Go!!

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