Cold Water Sparging

This is an experiment that I wanted to try for a while: Sparge a mash with cold instead of hot water.

Based
on my understanding of the lauter process sparging with cold water should have no or only little
impact on the efficiency if all the sugars, that will be dissolved, are
dissolved during the mashing process. While a colder sparge could slow
the speed of the run-off by causing the wort to be more viscous and
flocks of coagulated protein be smaller it should not affect how many
sugars are left behind. Especially in batch sparging where there is no
concern about channeling through the grain bed.

I decided to give
the cold water sparge a try on one of my Schwarzbier recipes. But since
I also wanted to change the grain bill slightly it is not a true
side-by-side where only the temperature of the sparge water changed.
Here is what I did for the two beers:


 

Schwarzbier IIIa

Schwarzbier IIIb

water

85 ppm Ca, 11 ppm Mg, 25 ppm Na, 17 ppm SO4, 38 ppm Cl, 175 ppm
HCO3

RA: 74 ppm as CaCO3

85 ppm Ca, 11 ppm Mg, 25 ppm Na, 17 ppm SO4, 38 ppm Cl, 175 ppm
HCO3

RA: 74 ppm as CaCO3

grist

63% Pilsner

30% Munich II

4% CaraMunich III

3% Carafa II

53% Pilsner

40% Munich II

4% CaraMunich III

4% Carafa II special

mash

63C; 30 min; pH = 5.48 (cold
sample)

heating at 1 C/min

70C for 50 min

heating at 1 C/min

76C for 15 min

63C; 30 min; pH = 5.44 (cold
sample)

heating at 1 C/min

70C for 50 min

heating at 1 C/min

76C for 15 min

sparge

single batch sparge

11 liter 75C (170F) water; the 2nd runnings
started to run bright after recirculating

single batch sparge

11 l 15C (60F) water; the 2nd runnings never
cleared up

efficiency

conversion: 98%

lauter: 89%

into kettle: 89%

post boil and chilled in kettle: 89%

conversion: 99%

lauter: 88%

into kettle: 86%

post boil and chilled in kettle: 88%

hops

0.87 g/l; 60 min; Hallertauer Trad. 6.8%

0.65 g/l; 20 min; Hallertauer Trad. 6.8%

1 g/l; 60 min; Hallertauer Trad. 6.6%

0.68 g/l; 20 min; Hallertauer Trad. 6.8%

boil time

60 min

60 min

starting extract

13 Plato

13 Plato

yeast

WLP 830; actual pitching rate unknown. All the 17l of wort were
pitched with that yeast.

WLP 830; maybe 30-40 ml sediment to 6l wort. Remaining 11l
were pitched after 24 hrs.

cellar

primary: 11 days at 10C (50F)

maturation: 3 days at 12C (54F)

cold conditioning: 3 weeks at 0C (32F)

primary: 7 days at 10C (50F)

maturation: 3 days at 12C (54F)

cold conditioning: 4 weeks at 0C (32F)

stats

attenuation limit 80%

actual attenuation: 78.5%

final extract: 2.8 Plato

attenuation limit 79.2%

actual attenuation: 78.5%

final extract: 2.8 Plato

 

The things to note is that the conversion efficiency was very high on both batches. Almost all of the extract potential was realized in the mash which is an indication for good and complete mashing. The lauter efficiencies (percentage of dissolved extract that made it into the kettle) for both beers were very similar and as a result the efficiencies in the kettle were very similar as well. The differences that can be seen are easily within measurement errors.

This shows that a cold water sparge does not necessarily lower your efficiency. 

It should also be noted that the 2nd runnings, which were the cold runnings, never cleared up. The remained hazy throughout the sparge. 

Tonight I tasted the beers. Here are pictures that show the color and clarity of the beer

 


 

And the taste notes:


 

Schwarzbier IIIa

Schwarzbier IIIb

aroma

- slightly roasty

- otherwise clean

- slightly roasty by less than IIIa

- slight sweetness in aroma

appearance

- dark mahogany color

- dark mahogany color. a little less than IIIa

- slightly hazier than IIIa

head retention

- seems a little less stable than the head of IIIb

- slightly more stable

taste

- sweet start

- followed by slight roast

- low bitterness that lingers only briefly

- sweet start

- followed by slight roast

- low bitterness that lingers only briefly

mouthfeel

- medium (compare to standard Pils)

- slightly fuller than medium

The cold sparged beer is definitely a slightly more hazy than the hot sparged version. This may actually have been the result of the cold sparge although I don't have a solid explanation for this. If the haze results from an increased protein content it may also explain the slightly better head retention and fuller mouthfeel.

Conclusions:

  • Cold sparging does not have strong adverse effects on efficiency and beer quality
  • when a mash-out is performed it has no apparent effect on the fermentability of the wort. I don't know if this is still the case when no mash-out is done.
  • it may make the beer more prone to haze
  • it does not really save time since the wort at the end of the lauter will be colder and require more time to be heated to boiling temperatures
  • it can save the need for a pot for heating the sparge water
  • Since the spent grain temperature is lower at the end of a cold sparge less energy is wasted.

While this was an interesting experiment I don't plan to repeat it in the near future. At this point I don't see any benefit in this practice except for cases were I forget to heat the sparge water.


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