Experimental Double Batch Brew

After reading an article in the Craft Brewing Association‘s magazine Brewer’s Contact which indicated that beer that is sparged too much may have some off tastes, I decided to try a bit of an experiment.

The plan was to collect two seperate runnings from the sparge, dilute the first runnings to match the second, and then treat both runnings the same in terms of hops, boiling, etc. Then to compare the tastes.


The recipe is almost the same as the previous batch (Wild Hop Beer), which actually gives us 3 things to compare.

Grain quantity est. og
Pale Malt 5Kg 40.45
Crystal Malt 750g 5.5
Chocolate Malt 30g 0.22
Torrified Wheat 250g 1.87

Giving total expected og=1048 and fg=1011

I expected to make two batches each of about half the normal amount of 25L, however things didn’t work quite to plan.

Mashing was more or less the same as before… 2.5Gallons of boiled water dropped to mash tun and cooled to 170F. Grains stirred in and temperature adjusted to 150F and left for 90 minutes.

This is when I realised my first major mistake… I had forgotten to put the manifold inside the mash tun! Not a problem I emptied out the mash into stockpot, replaced the manifold and put the grain back in and left to settle for a few minutes. The first runnings were very cloudy, so I recirculated the initial runnings for quite a while until they became clearer (note recirculating means collecting some wort in a jug from the run off tap and pouring it carefully back into the top of the mash tun).

My second mistake was not calculating what I was planning to collect. Partly this was because I had no idea on how the sugar level changes as sparging proceeds, and secondly because I hadn’t really thought about it, so had to quickly do some adhoc arithmetic.

I started sparging and collecting first runnings. Whilst sparging I regularly measured the brix against the amount of wort collected as I thought it could be useful in the future. The measurements I made were:

Liters collected brix Collected Brix
0 22.8%
1 22.7%
5 22.5%
8 17.4%
10 15.0% 20.7%
13 12.2% 19%
18 10.8%
20 10.6%
26 5%

This needs to be put into a graph to make any sense of it.

Note I stopped collecting when brix was still 5% (aprox 1020 sg), because otherwise my second runnings would have become too dilute.

I ended up with two batches:

First Runnings: 14 Liters, brix=19.0%, og=1076
Second Runnings: 15 Liters, brix=8.2%, og=1033

First Runnings

Topped up with 15 Liters more water. After the boil was left with 15 Liters @ 15.4% brix to which another 8 liters of water were added to dilute it.

Hops at start of boil were:

Type alpha quantity ebu
Goldings 5% 20g 6.7
Wild 4% 20g 5.3
Target 10% 10g 6.7

Total ebu=18.7

15 minutes before end of boil, I added 10g Goldings and 10g Wild hops and teaspoon of Irishmoss.
5 minutes before end of boil I added 10g Goldings and 10g Wild hops.

Yeast was Brupacks top fermenting yeast made with a starter of 30g DME. This yeast was shared between the two batches.

Second Runnings

I didn’t dilute this as it was already fairly weak (15 Liters, og=1033).

Hops at start of boil were:

Type alpha quantity ebu
Goldings 5% 12g 6.7
Wild 4% 12g 5.3
Target 10% 6g 6.7

Total ebu=18.7

This is the same proportion as for batch 1 but reduced to account for lower volume.

15 minutes before end of boil, I added 6g Goldings and 6g Wild hops and teaspoon of Irishmoss.
5 minutes before end of boil I added 6g Goldings and 6g Wild hops.

After boil, brix=9.4%

Cooling was not a problem this time because Colin from the Oxford Brewing Group had provided me with extra tubing and fittings to connect the tap to the immersion chiller.


Both batches were fermented for 4 days and then racked to secondary fermenter where they stayed until May 22nd (5 weeks) and then bottled. Half the first runnings were put into a 10L polypin. Primed with 75g DME shared between both batches in proportion to volume.
First Runnings are in green-topped bottles. Second Runnings in Red-topped.


Initial tasting while bottling is favourable… even without conditioning they both taste good, but the first runnings taste smoother.

I will be taking samples of both batches to the Taste and Swap tomorrow where I hope to get more feedback on the taste differences between them… although they have not had much time to condition.

One thought on “Experimental Double Batch Brew

  1. Unfortunately at the taste and swap meeting, the 2nd runnings had a horrible acetone taste to it! This was not there when I bottled, so it may be a problem with the bottles not being rinsed properly after cleaning… or maybe just a bad bottle.

Leave a Reply