Saturday, January 22, 2011

Lambic 1 - Turbid Mash

With the multitude of different microorganisms present in the fermentation, lambic brewers typically tailor their wort composition to provide food for the various critters over the multi-year fermentation.  There’s arguably no set “perfect” regiment, and each brewer’s mash schedule tends to be slightly different due to economic and equipment constraints.  Using the system that we built as it was designed to perform, we decided that a modified turbid mash would give us the best shot at producing a traditional lambic.

 The basic premise of a turbid mash is to minimize the nutrients available to the organisms typically active early on in the ferment and to maximize those that feed  and grow during the latter part of the multi-year cycle.  To accomplish this, a multi-step mash is performed where early on, a significant portion of mash liquor, rich in ungelatinized starches, is removed from the mash and held at a temp near boiling to effectively denature the enzymes.  This liquor is eventually reintroduced to the main mash after it has  been run through its various conversion rests, resulting in a final wort low in protein and high in long-chain dextrins and starches.  

Here’s how we accomplished this:

Starch rich liquid pulled from the mash, 180 degrees.
  1. We started off placing the entire grist into our boil kettle (7lbs German Pils and 4.15 lbs raw, soft white wheat).  
  2.  To the grist, we added 3.35 qts of 141 degree water to arrive at a dough-in temp of 113 degrees.  We normally dough in right to the mash tun, but with such a low water to grain ratio, it was important to make sure that all the grain was mixed thoroughly and we were afraid that the dip tube and false bottom in the mash tun would make this difficult.
  3. After the grain was thoroughly wet, we transferred it to our recirculating mash tun.  The system requires about 2 quarts of liquid before recirculation can occur, so in total now, there were about 5.35 qts in the mash.  The grain initially absorbed just about all of the 3.35 qts and so without this additional 2 in the mash tun, circulation would be non-existent.
  4. After letting the mash rest for about 20 minutes, we added 5 qts of 212 degree water to bring the temp up to 136 degrees.  A few minutes before this addition, we cut the recirculation pump and increased the temperature of our hot liquor tank to 136 so that once we made the water addition and restarted the pump, the temperatures would be in equilibrium (We continued to use this same process for the rest of the temperature increases).
  5. 5 minutes later we collected 2 qts of the extremely starchy mash liquor from the recirculation output tube and held this on a stove at a temperature of about 180 degrees.  This effectively denatured the enzymatic activity in the liquid.  The rest of the mash rested for about 20 minutes.
  6. Next, we added about 6 qts of 212 degree water to bring the temp up to 150 degrees where it rested for 40 minutes.
  7. For the second pull, we collected 4 qts of the mash liquor and added it to the previous pull.  We also increased the temp of this collective wort to about 209 degrees.
  8. Immediately after the second pull, we added 6 qts of boiling water to bring the mash temp up to 162.  Rest time, 10 minutes.
  9.  Next we added back all of the 209 degree pulled wort which brought the total mash temp up to 168 degrees.
  10. After a 10 minute rest, we started the sparge with 190 degree water.  This temp is normally too high for a regular sparge, but knowing that the leached tannins will break down over the long fermentation, the higher temp was beneficial in helping extract out any remaining sugars and unconverted starches from the grain.
With a turbid mash, since a significant portion of the enzymatic rich liquid is removed and denatured early on, mash efficiencies are typically really low.  Long, high volume sparges are common place in order to extract out all of the available sugars.  We were expecting this to be the case, but after an hour and fifteen minutes with about 6 gallons collected in the kettle, we decided to take our first gravity reading….1.056!  We were shooting for a gravity of 1.044 at 5 ½ gallons and since apparently we didn’t account for the recirculation factor, we ended up with a significantly higher efficiency than we were expecting ( ~82%).

Sour Starter
Although a long boil to concentrate the wort down to our intended original gravity was not necessary anymore, we still wanted to conduct a fairly long boil.  With such a large portion of raw wheat, the long boil helps to coagulate the proteins and also precipitate out a lot of the tannins from the hot sparge.  Although we didn’t age them ourselves, I recently purchased some 3-yr old Willamette hops from FresHops that we added at the beginning of the 2 ½ hr boil.  This long boil also helps to “extract as many of the antibacterial humulones, hulupones, and preserving polyphenols as possible” (Sparrows,  Wild Brews).

After chilling the wort down 67 degrees, we pitched about a ¼ of a packet of Wyeast  3787 Trappist High Gravity yeast.  Over the previous few weeks, I had been collecting the dregs of numerous commercial sour beers (Isabelle Proximus, Vagabond and Gargamel, Deviation, Giardin Gueuze, etc)  in a small starter consisting of a low gravity commercial wheat ale, a small amount of fresh wort, and some large oak cubes.  The idea was that the various microorganisms would inhabit the wood of which I could then use to inoculate future pre-wild worts.  Since the starter was still relatively fresh, I added about a half cup of the liquid and dregs directly to our carboy at the same time as the 3787. 

 Lambic - Turbid Mash

Recipe Specifics

Batch Size (Gal): 5.5
Total Grain (Lbs): 11.15
Anticipated OG: 1.044
Anticipated SRM: 4.1
Anticipated IBU: 19.0
Brewhouse Efficiency: 82 %
Wort Boil Time: 150 Minutes
Anticipated ABV: 5.4%

62.8% - 7.00 lbs German Pilsner
37.2% - 4.15 lbs Raw, White Wheat

80 grams Willamette (Whole, 3 yr aged, 1.5% AA) @ 150 minutes

Wyeast 3787 Trappist High Gravity (1/4 packet)
Sour dregs starter (Isabelle, Gargamel, Vagabond, Deviation, Giardin Gueze, etc - 1/2 cp)

Water Profile & Additions
Charcoal filtered Seattle water
Added to boil (forgot to add in the Mash):
1.0 grams per gallon Calcium Chloride
0.2 grams per gallon Gypsom
0.24 grams per gallon Epsom Salt
0.1 grams per gallon Sodium Chloride

Mash Schedule
 Turbid Mash - see above

Brewed 8/14/2010 - with Blake

Raw, soft white wheat was purchased at Wholefoods.

Collected 6 gallons of 1.056 wort.  Removed about 0.9 gallons and then topped up with 2 1/2 gallons of water (after a 150 minute boil, we should be left with 6 gallons of 1.044 wort).

Boiled for 150 minutes with hops added at 150 minutes in a hop bag.

Chilled to 67 degrees and then added wyeast and commercial dreg slurry. Fermented at 68 degrees for 14 days.

8/28/2010 - Racked to secondary.  Traditionally we wouldn't do this as the decomposing yeast acts as food for some of the microorganisms during the long ferment, but we wanted to use the yeast cake for Lambic Batch 2.

9/11/2010 - Racked lambic batch 2 off of yeast cake and into secondary.  The yeast cake was then split into two and half was added back to Lambic batch 1 and half to Lambic batch 2 for the remainder of the long fermentation.

1 comment:

  1. Have you sampled this recently? I'd love to hear on how it's progressing.


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