Ajhutch
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Yesterday I had a brewday with no distractions and no time constraint. I am also past due to make this year’s long aged sour beer. So I decided to take on a more complex challenge and try my own version of the traditional lambic turbid mash. I thought it was worthy of a write up and some photos.
The turbid mash effectively involves multiple different temperature rests, along with pulling wort out out of the mash tun at the end of some rests, and heating it to above enzyme temperatures. This means that there is a variety of different length starches and sugars in the final wort, which provides a variety of food for the yeast and bacteria to munch on over the multi-year fermentation. This should lead to a complex and interesting beer at the end.
(Without going too far into the more prosaic reason why the lambic brewers do this, there was once a tax in Belgium which was assessed based on mash tun size, so you can imagine that seeking to get more beer out of a smaller mash tun would be a factor in the development of the technique.)
I used this article by Michael Tonsmeire as my guide for the brewday schedule. https://www.themadfermentationist.com/2009/08/lambic-3-turbid-mash.html
While I did my best to adjust for my equipment, I consistently over estimated the amount of water required at each infusion to raise the temperature, so ended up using some cold water and therefore with a thinner mash than the plan here:
Started with 3kg of pilsner malt and 2kg of flaked wheat.
I was using my usual setup of brew in a bag with my 30L stainless steel pot, supplemented by a stock pot to heat infusion/sparge water.
The mash steps were:
20 mins at 45C
10 mins at 58C
30 mins at 64C
30 mins at 72C
The first step is seriously thick, it’s only just above what grain will absorb, so I actually did that in the smaller pot so the heating element and false bottom tube in the big pot didn’t interfere. I took half the water out into jugs, shoved the grain in and then poured the jugs back over the grain. There was no point attempting a proper dough in at this stage as it was just too thick. I doughed in properly when I baled the mash into the big pot at the start of rest 2. Here is the first step:
I raised each temperature rest via a water infusion so the mash also gets thinner as it goes, though this is counteracted somewhat by the removal of the turbid wort. Wort was drawn out of the mash after steps 2 (1 litre) and 3 (4.5 litres) and heated up to 85C to stop the enzyme activity. Here is a sample of this turbid wort, which was added back to help reach mash out temperature.
The batch sparge I did was at close to 90C. This is substantially higher than normally advised and will cause tannin extraction. But this is just more food for the wild yeast and bacteria in these long aged sour beers, which are traditionally fermented in oak anyway.
Because of the extra liquid added to cool at the various steps, and then forgetting to adjust my sparge volume accordingly, I ended up with 31 litres pre boil instead of 28. Which is a problem as my pot is 30 litres. So I started the boil in both vessels and added back to the big pot once there had been enough boil off. The boil was long, about 2 hours, and used 15g of aged low-alpha acid hops. You’re not looking for bitterness or hop flavour in this beer, just the preservative effect of the hops. Here’s what 15g of very old hops looks like on an IKEA kids dinner plate.
One feature of this multi step mash and the hot sparge is the brew house efficiency is far higher than I usually get. I ended up with 25 litres at 1.047 which is 85% BHE, I normally get 68-70%.
All in all an enjoyable brewday but one that definitely needs time and peace and quiet. The mash and sparge aren’t that much longer than normal, but there is a lot more work involved because of managing the infusions and turbid pulls. Then the long boil, so it was a long day, but if beer turns out well I will definitely do it again.
The beer is now tucked away with White Labs WLP655 Belgian Sour Blend working on it. In about 3 months I’ll rack it from the bucket into a better bottle or glass carboy for long term aging. This is the second year I’ve brewed a lambic style beer and eventually I will blend a portion of them, it also likely that some will end up being used with fruit along the way.
The turbid mash effectively involves multiple different temperature rests, along with pulling wort out out of the mash tun at the end of some rests, and heating it to above enzyme temperatures. This means that there is a variety of different length starches and sugars in the final wort, which provides a variety of food for the yeast and bacteria to munch on over the multi-year fermentation. This should lead to a complex and interesting beer at the end.
(Without going too far into the more prosaic reason why the lambic brewers do this, there was once a tax in Belgium which was assessed based on mash tun size, so you can imagine that seeking to get more beer out of a smaller mash tun would be a factor in the development of the technique.)
I used this article by Michael Tonsmeire as my guide for the brewday schedule. https://www.themadfermentationist.com/2009/08/lambic-3-turbid-mash.html
While I did my best to adjust for my equipment, I consistently over estimated the amount of water required at each infusion to raise the temperature, so ended up using some cold water and therefore with a thinner mash than the plan here:
Started with 3kg of pilsner malt and 2kg of flaked wheat.
I was using my usual setup of brew in a bag with my 30L stainless steel pot, supplemented by a stock pot to heat infusion/sparge water.
The mash steps were:
20 mins at 45C
10 mins at 58C
30 mins at 64C
30 mins at 72C
The first step is seriously thick, it’s only just above what grain will absorb, so I actually did that in the smaller pot so the heating element and false bottom tube in the big pot didn’t interfere. I took half the water out into jugs, shoved the grain in and then poured the jugs back over the grain. There was no point attempting a proper dough in at this stage as it was just too thick. I doughed in properly when I baled the mash into the big pot at the start of rest 2. Here is the first step:
I raised each temperature rest via a water infusion so the mash also gets thinner as it goes, though this is counteracted somewhat by the removal of the turbid wort. Wort was drawn out of the mash after steps 2 (1 litre) and 3 (4.5 litres) and heated up to 85C to stop the enzyme activity. Here is a sample of this turbid wort, which was added back to help reach mash out temperature.
The batch sparge I did was at close to 90C. This is substantially higher than normally advised and will cause tannin extraction. But this is just more food for the wild yeast and bacteria in these long aged sour beers, which are traditionally fermented in oak anyway.
Because of the extra liquid added to cool at the various steps, and then forgetting to adjust my sparge volume accordingly, I ended up with 31 litres pre boil instead of 28. Which is a problem as my pot is 30 litres. So I started the boil in both vessels and added back to the big pot once there had been enough boil off. The boil was long, about 2 hours, and used 15g of aged low-alpha acid hops. You’re not looking for bitterness or hop flavour in this beer, just the preservative effect of the hops. Here’s what 15g of very old hops looks like on an IKEA kids dinner plate.
One feature of this multi step mash and the hot sparge is the brew house efficiency is far higher than I usually get. I ended up with 25 litres at 1.047 which is 85% BHE, I normally get 68-70%.
All in all an enjoyable brewday but one that definitely needs time and peace and quiet. The mash and sparge aren’t that much longer than normal, but there is a lot more work involved because of managing the infusions and turbid pulls. Then the long boil, so it was a long day, but if beer turns out well I will definitely do it again.
The beer is now tucked away with White Labs WLP655 Belgian Sour Blend working on it. In about 3 months I’ll rack it from the bucket into a better bottle or glass carboy for long term aging. This is the second year I’ve brewed a lambic style beer and eventually I will blend a portion of them, it also likely that some will end up being used with fruit along the way.
