Spontaneous Fermentation Project Part 3 -- The recipe and brewday - Brain Sparging on Brewing


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January 5, 2014

Spontaneous Fermentation Project Part 3 -- The recipe and brewday

In the first two parts of the series on this spontaneous fermentation project I discussed process and goals. Today's it's time to get into the recipe and brew day. I'm closely following the process I used to brew Year Four's wort for the lambic solera. Same basic grain bill and turbid mash I used there. It's a long process but it's an interesting way to spend the brew day. Having done it once I feel less apprehensive about trying it again. Anyway, let's get into the recipe.

Spontaneous Fermentation Project Recipe

Batch size: 5 gallons
Efficiency: 72%
Est. ABV: 6%
Color: 3.6 SRM
IBUs: 8.6
Est. OG: 1.058
Est. FG: 1.002

Grain bill

5lb unmalted red wheat [1.7 SRM] 45%
6lb Weyermann pilsner malt [2 SRM] 55%


Yellow balanced profile in Bru'n Water
5.7 gallons mash water
2.86 gallons sparge water

Water Additions:

1.7g gypsum
1.7g epsom salt
0.3g canning salt
2.3g calcium chloride

0.9g gypsum
0.9g epsom salt
0.1g canning salt
1.1g calcium chloride
1.5ml lactic acid

Mash Schedule

1. Dough in 1.3 gallons at 134F for 15 minute rest at 113F
2. Add 1.1 gallons at 148F for 15 minute rest at 126F
3. Remove 0.75 gallons and heat to 190F and hold
4. Add 1.65 gallons at 185F for 45 minute rest at 149F
5. Remove 1.55 gallons and heat to 190F and hold
6. Add 1.65 gallons at 195F for 30 minute rest at 162F
7. Remove 2.1 gallons and heat to 190F
8. Add contents of the kettle to raise mash temp to 172F for 20 minutes
9. Vorlouf
10. Sparge with 2.86 gallons at 190F


90 minute boil
0.2oz Belma [12.10%] at 90 minutes (8.6 IBU)


Cool in shallow pans exposed outdoors until 60-70F. Rack to fermentor and ferment until complete.

And the brewday...

Long ass turbid mash took most of the day. I started milling (by hand) at 1pm and didn't even start sparging until almost 5pm. Actually not terribly longer than a full blown decoction mash but it still makes for a very long brew day, especially because the wort needs to cool before it can go in the fermentor.

As my second turbid mash attempt it was more fluid (pun not intended) and quicker because I had better expectations of what was going on and how to time things correctly. Still not perfect but getting closer. Runnings were far more milky than the first turbid mash, which I take to be a good thing. The picture to the right is the first decoction. Look at all that sweet starch.

The decocted portion of the mash tastes very starchy, unsurprisingly. After the portion at 149F came in the decocted portion started tasting a little sweet, which is also unsurprising.

The next picture, on your right, is a picture of the runnings from the last decoction. The mash temperature at this point is 162F so conversion is complete and as you can see the runnings are extremely clear. The mash was very loose at this point, which also contributes to the clarity of the runnings.

It's another one of my classic terrible photos but you can see on the top of the picture that the measurements in the measuring cup I was using can be seen almost to the bottom.

I wish I could figure out how to get a decent video uploaded to blogger but honestly as dicey as my ability to take still photos is I'd probably film something that looks like the Blair Witch Project. The reason why is that as the decocted portion of the mash is heating up you can see all the starch rolling around in the kettle. It's very lava lamp-like.

Pre-boil volume: 7.4 gallons
Pre-boil gravity: 1.037
Mash efficiency: 67%

Way, way too much wort but the efficiency isn't too bad for a wort full of starch. I had to boil some of the wort on the stove to try to boil off more of the wort. My turkey fryer kettle only holds 7.5 gallons so it wouldn't all fit with a rolling boil.

The picture below is of my cheap ass coolships. Half the kitchen went into making this beer. Seriously.

It's in the mid-20s while I'm trying to cool the beer, which is helpful because the beer is cooling to room temperature fairly quickly. I'm concerned it's going to cool too quickly to get a good population. The wort is starting to get ice crystals after sitting out for about an hour. The most shallow vessel, a cookie sheet, froze over in about fifteen minutes. Definitely no overnight cooling going on. It's windy so at least that should help blow a lot of yeast and bacteria into the wort. If it warms a little later in the week I may draw some of the wort out and stick it outside for a few hours to collect a larger population.

Collected right around five gallons at 1.046 gravity. A little low on efficiency but again not surprising due to all the unconverted starch.



  1. man, i cant wait to see how this came out.

  2. It's definitely active. I'm taking pictures roughly every 24 hours and putting them together in the next post. My plan is to keep taking pictures daily until it stops doing anything interesting.

  3. Awesome project man! Saw your post on the AHA forum and checked out your blog. I was thinking a cookie sheet would make a great coolship so I'm glad someone tried it already. Did you have better luck with the cookie sheets or the pyrex?

  4. I used both together so it all seemed to work out fine. The pyrex was a little easier to move around because it's sturdy and has handles but the cookie sheet is more shallow so it will cool the beer faster. It was in the 20s that night so everything cooled in a hurry regardless. The cookie sheets were a PITA because wort sloshed out easily while trying to pick it up and drain it into the fermentor so I'd recommend using something deeper and more stable. The baking pans I used worked well and they were a little easier to move.