Tuesday, November 5, 2013

IPA Experiment | Does Chloride to Sulfate Ratio impact perception of Bitterness

Recently, BeerAndWineJournal.com and Basic Brewing made a call for all of their readers and listeners to participate in an experiment.

"Does the Chloride to Sulfate ration in your brewing liquor influence the perception of hop bitterness in the final beer."

Here are the basics:
We were to brew an IPA using the parameters outlined.  Then during bottling, add specific amounts of Gypsum (Calcium Sulfate) after each gallon.  Then during the sampling, we needed to observe whether the different Gypsum additions had any impact on the bitterness of the finished beer.

Brew Day: 10/5/2013 
Dry-hopped: 10/17/2013
Bottled: 10/22/2013
Bottle conditioned till 10/31/2013

(The following is quoted from beerandwinejournal.com)

Brewing the Base Beer

The experiment is simple, brew 5.0 gallons (19 L) of IPA with a 1:1 chloride-to-sulfate ratio, then adjust the ratio as you bottle. To do this, on brewday, start with distilled water, RO water or tap water that has been diluted with distilled water to 25 ppm bicarbonate or less. Then, add calcium to your water by adding both calcium chloride and gypsum. For 10 gallons (38 L) of water, add 4.0 g (a little over 1 tsp) of calcium chloride and 4.0 g (about 1 tsp) of gypsum to get to 50 ppm calcium, with a 1:1 chloride-to-sulfate ratio. Make the wort, ferment it and get ready to bottle.


When you bottle, you will bottle 1.0 gallon (3.8 L) of beer at the existing 1:1 chloride to sulfate ratio. For each subsequent gallon (3.8 L) you bottle, you will add gypsum to yield bottles at 1:2, 1:3, 1:4 and 1:5 ratios, respectively. Here’s how to do that. Bottle the first gallon (3.8 L) as you normally would, and label these bottles with a “1.” Then, add 1.5 g of calcium sulfate to the remaining 4.0 gallons (15 L) of beer. To prevent foaming, wet the gypsum before adding it (see below for more). Stir to dissolve the gypsum into the batch, but not so much that you splash and aerate the batch. Let the beer sit for 2 minutes (so the dissolved gypsum evens out), then bottle the second gallon. Label these bottles with a “2.”
For the third gallon (3.8 L), add 1.0 g of gypsum and label the bottles “3.” For the fourth and fifth gallons, add 0.75 g and 0.33 g of gypsum, respectively. Label the bottles “4” and “5,” as appropriate.

My IPA Recipe/Procedure

13lb - 2 Row Pale Malt
1lb   - C-60

1oz Magnum - 1st Wort
.5oz Magnum at each time - 55 min, 45 min, 35 min, 25 min
1oz Cascade - 5 Minutes
1oz Cascade - Flame Out
2oz Cascade - Dry Hopped for 6 days

Wyeast 1056 (1qt starter from smack pack)

152 F for 7hrs (much longer than was necessary but I had family matters to attend to during this time)

1 hour


Priming Sugar:
4.2oz Dextrose

Each gallon consisted of two (2) 8oz Coke bottles and nine (9) 12oz amber bottles. This only equals 124oz.  Even though a full gallon is 128oz, I didn't feel this was a big deal.

After each gallon bottled, I would add Gypsum in the following amounts.

1st Gallon   - 1:1 Ratio - I did not add any addition Gypsum for the first gallon.
2nd Gallon - 1:2 Ratio - Added 1.5g Gypsum
3rd Gallon  - 1:3 Ratio - Added 1.0g Gypsum
4th Gallon  - 1:4 Ratio - Added .75g Gypsum
5th Gallon  - 1:5 Ratio - Added .33g Gypsum

I then let the beer bottle condition for nearly 9 days.

Results of the Experiment

To give a better indication of sensory observation, I decided to do a blind tasting of each sample.

I blindly covered all distinguishing marks on each bottle using masking tape.  I then label each bottle and 5 glasses with A-B-C-D-E

Any deviations from the process recommended in article:

  1. Even though my bottling bucket read perfect measurements after each gallon bottled, the 1:5 ratio only had 100oz bottled instead of 128oz.
  2. My digital scale only measures in whole grams. It does not do decimal points. I measured as closely as possible. Did some math and cut lines like a coke (cocaine) head. So hopefully I was close enough. 

Sensory observations:


Head & Retention

All samples had heads consisting of small (almost nitrogen-like) creamy bubbles.

A (1:3)-Small head and sticking around
B (1:5)-Small head and Falls fast.
C (1:1)-Nice thick head. Had 2nd best staying power.
D (1:4)-Nice Thick head. Had the best staying power.
E (1:2)-Nice head on the pour but it fell quickly. But not at bad as A & B.

At beginning of the Experiment (50F)
Order of head retention from least to greatest.
B (1:5) - A (1:3) - E (1:2) - D (1:4) - C (1:1) (at beginning of the experiment)

After Swirling At end of experiment (60F):
E (1:2) - Had absolutely no head retention after being swirled. It fell immediately. 
A (1:3) & B (1:5) – Not as bad as E but almost.
C (1:1) – Was closed to D, but not equal.
D (1:4) – Had the best head retention over time.

They were all citrusy.
The bouquet was the same throughout all of them.

On all of the samples, the mouthfeel was very big. Not like James Spencer's All- Rye beer, but from the perfect carbonation. Very very creamy. 

Beginning of Tasting (50 degrees F)
They were all very similar. To pull out anything, I had to do about 15 minutes of sipping. I let them warm up and re-sampled. It's very difficult to tell a difference in any of the samples.
A & E are nearly identical in every way.
A (1:3), B (1:5), & E (1:2)- Have a mellow bitterness. It doesn't bite.
D (1:4) - Is a step above A B & E in the bitterness and flavor.
C (1:1) -Noticeably different. With the most distinctive bitterness. A little sharper than the rest. Not harsh, but more distinct.

End of Tasting (around 65 degrees F) Most bitter to least bitter:
C (1:1) – Most distinctive. Still stands out.
E (1:2) & A (1:3) – Are about the same. Much less than C (1:1) but not as minimal as D (1:4) & B (1:5).
D (1:4) & B (1:5) – Definitely the least perception of bitterness. 

What are your conclusions?


My results seemed to show that the More Calcium Sulfate that is added, the less sharp the bitterness becomes.

The perception of bitterness in the 1:2 thru 1:5 changed slightly a the beer warmed. However, 1:1 remained the most distinctive.

I think that if I'd brewed, specifically (from start to finish) a 1:2 and a 1:3, etc that the results might have been more pronounced.

I think that the chemicals didn't meld well with the alcohol in the finished beer so therefore did not result in a pronounced difference between the samples.

    The differences in the samples were so slight that if you weren't spending

the time to sip each individual sample, you would never know the difference. NEVER. 

Youtube Videos

For each date listed below, I will be posting a youtube video.  Just click on the link and you will be taken to the correct video.

(Brew Day: 10/5/2013 --- Dry-hopped: 10/17/2013)
Bottled: 10/22/2013Bottle conditioned till 10/31/2013

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