effect of mash and wort acidification versus yeast
TRANSCRIPT
Effect of Mash and Wort Acidification Versus
Yeast Pitching Rate As Parameters to Optimize
Fermentability of Adjunct Worts
SONGSAK HENGPRATHANEE
1
Brewing Process
2
Raw Materials
3
Malt
Carbohydrates
Proteins
Minerals
Vitamins
4
Malt
Why are essential nutrients for yeast so
important in brewing?
5
Yeast Food Beer
6
Yeast Wort (Nutrients)
Alcohol CO2
Beer flavour
Fermentation
7
Extract
Fermentation: Fermentable Extract
Fermentation end: Non-fermentable Extract
BH : Original Extract (Sugars, FAN and etc)
Residual Extract 8
Rice (A local raw material)
85-90 % Starch 5-8 % Proteins 0.2-0.4 % Oil and Inorganic substance
9
Rice & Barley
Nutrients Rice Barley
Carbohydrates 85-90 % 70-85%
Proteins 5-8 % 10.5-11.5%
Inorganic matter 0.2-0.4%
2.0-4.0%
Fats or Oils 1.5-2.0%
10
Brewing with Rice
Malt
Water
Hop
Yeast
Some parameters have to be optimized
Rice Beer
11
12
Brewing with Rice
Decoction process
High gravity brewing
Rice mash was boiled and pumped into malt mash
Yeast pitching rate
1.5 million cells / % plato / ml of CW
Overview
13
Wort Acidification
Brew house part
Fermentation part
pH pH levels during various stages of the brewing process affect many parameters of the beer.
Extract yield
Beer Color
Hop yield Foam Stability
14
15
pH
Enzyme
Beer parameters
Temp
pH in Mash
Enzymes Opt. pH Affected parameters
Endopeptidase Carboxy peptidase
Dipeptidase Aminopeptidase
4.9-5.1 5.1-5.3 8.1-8.3 7.1-7.3
FAN, Foam stability, color
β glucanases 4.7-5.0 Filtration ability
β-amylases 5.4-5.5 Extract potential
α-amylases 5.6-5.8 Extract potential
16
Wort Acidification Organic acid
Mineral acid
Lactic acid Biological
Industrial
Phosphoric acid
Hydrochloric acid
Sulphuric acid
17
- Adjust pH in Mash (pH 5.4-5.6) - Adjust pH in Boiled Wort (pH 5.2-5.4)
Trial Design
Trial 2: “No Lactic acid”
Trial 1 : “Lactic acid addition”
Control : Same Brewing Procedure 18
Analysis Parameters Chemical Analysis • pH • Extract • VDK • Flavor profile
Microbiological Analysis • Yeast cell count • % dead
Sensory Analysis 19
Trial Lactic acid addition
No Lactic acid
Original extract 13.63 13.66
pH of Mash 5.53 5.72
pH of Cold wort 5.34 5.53
Bitterness of AW 28.0 29.0
FAN 115.4 102.1
Wort Result
20
80.48% 80.19%
70.00%
72.00%
74.00%
76.00%
78.00%
80.00%
82.00%
Lactic Acid Addition No Lactic Acid
Brew House Yield
21
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
0 1 2 3 4 5 6 7 8 9 10 11 12 13
Lactic acid Addition No Lactic acid
Extract reduction rate of both trials were quite similar
App Extract (%)
22
Cell In Suspension (mio/ml)
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00
100.00
0 1 2 3 4 5 6 7 8 9 10 11 12 13
Lactic acid Addition No Lactic acid
Max CIS of Lactic acid addition trial
was higher CIS of both trials were
similar
23
pH
3.80
4.00
4.20
4.40
4.60
4.80
5.00
5.20
0 1 2 3 4 5 6 7 8 9 10 11 12
Lactic acid Addition No Lactic acid
pH of Lactic acid addition trial was
higher
pH reduction rate of Lactic acid addition
trial was faster
24
VDK (mg/l)
0.00
0.50
1.00
1.50
2.00
2.50
3.00
0 1 2 3 4 5 6 7 8 9 10 11 12 13
Lactic acid Addition No Lactic acid
Max VDK of Lactic acid addition trial
was lower
VDK of both trials were
similar
25
FT Lactic acid addition
No Lactic acid
Fermentation time (D) 12 12
Residual Extract (%) 1.91 2.01
Attenuation limit(%) 1.90 2.00
pH 4.07 4.00
Fermentation End
26
FT Lactic acid addition
No Lactic acid
Yeast cropping ratio 2.47 2.23
Dead cell of Cropped yeast (%)
6.30 8.50
Fermentation End
27
Finish Goods
Trial Alcohol (% v/v)
App Ext (%w/w)
pH ADF* (%)
Lactic acid addition
5.00 1.51 4.08 86.21
No Lactic acid 4.99 1.59 4.04 85.65
*ADF = Apparent Degree of Fermentation 28
Higher Alcohol
11.02 15.03
73.70
9.91 12.13
71.01
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
1-Propanol (ppm) Isobutanol (ppm) Isoamylalcohol (ppm)
Lactic acid addition No Lactic acid 29
Aldehyde and Ester
1.63
12.41
1.05 2.02
11.78
0.88
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
Acetaldehyde (ppm) Ethyl acetate (ppm) Isoamylacetate (ppm)
Lactic acid addition No Lactic acid 30
Sensory Test Triangle test
Sample’s code Difference sample Correct Wrong Result
A/B/C A 1 7 ns.
Sample A : Trial 1 (Addition lactic acid) Sample B&C : Trial 2 (No lactic acid)
Statistic for different test is triangle test at 95% significance. Panelists couldn't detect difference of trials.
31
Lactic acid addition
Lower Residual extract
Higher pH in beer
Higher yeast cropping ratio and lower dead Cell
A little lower Acetaldehyde
A little more Ester and Higher Alcohol 32
Wort Acidification
Overview
Brew house part
Fermentation part
Trial 1 : Lactic acid Addition
Yeast pitching rate
33
Trial 2 : No Lactic acid
Yeast Pitching Rate
Yeast pitching rate is too Low
- Yeast get stressed
- Produce undesirable by product
- Incomplete fermentation
34
Yeast Pitching Rate
Yeast pitching rate is too High
- Lower growth rate - Lower yeast viability
35
Adjunct Wort
FAN is Lower
Protein in Rice is Lower than Malt
Should Yeast pitching rate be lower? 36
Trial Design
Trial 3 : “Lower yeast pitching rate”
Trial 4 : “Ref. yeast pitching rate”
Control : Same Brewing Procedure
Yeast pitching rate: 1.5 x 106 cells/%Plato/ml CW
Yeast pitching rate: 1.0 x 106 cells/%Plato/ml CW
37
Analysis Parameters Chemical Analysis • pH • Extract • VDK • Flavor profile
Microbiological Analysis • Yeast cell count • % dead
Sensory Analysis 38
Wort Result
Trial Lower yeast pitching rate
Ref. yeast pitching rate
Original extract 13.66 13.63 pH 5.33 5.34
FAN 115.0 115.4
39
1.50
3.50
5.50
7.50
9.50
11.50
13.50
0 1 2 3 4 5 6 7 8 9 10 11 12
Lower yeast pitching rate Ref. yeast pitching rate
Extract reduction rate of Lower yeast pitching rate trial
was slower
App Extract (%)
40
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00
0 1 2 3 4 5 6 7 8 9 10 11 12
Lower yeast pitching rate Ref. yeast pitching rate
Cell In Suspension (mio/ml)
Max CIS of lower yeast pitching rate
trial was lower
CIS of lower yeast pitching rate trial was
higher
41
3.80
4.00
4.20
4.40
4.60
4.80
5.00
5.20
0 1 2 3 4 5 6 7 8 9 10 11 12
Lower yeast pitching rate Ref. yeast pitching rate
pH
pH reduction rate of lower yeast
pitching rate trial was lower
42
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
0 1 2 3 4 5 6 7 8 9 10 11 12
Lower yeast pitching rate Ref. yeast pitching rate
VDK (mg/l)
VDK of lower yeast pitching rate trial was a little higher
Max VDK of lower yeast pitching rate
trial was higher
43
Fermentation End
FT Lower yeast pitching rate
Ref. yeast pitching rate
Fermentation time (D) 12 12
Residual Extract (%) 1.91 1.91
Attenuation limit (%) 1.90 1.90
pH 4.06 4.00
44
Fermentation End
FT Lower yeast pitching rate
Ref. yeast pitching rate
CIS (million cells/ml) 24.5 17.8
Yeast cropping ratio 2.08 2.47
Dead cell of Cropped yeast (%)
14.8 6.30
45
Finish Goods
Trial Alcohol (% v/v)
App Ext (%w/w)
pH ADF* (%)
Lower yeast pitching rate
4.97 1.50 4.11 86.32
Ref. yeast pitching rate
5.00 1.52 4.07 86.21
*ADF = Apparent Degree of Fermentation 46
10.94 14.55
78.67
11.02 15.03
73.70
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00
1-Propanol (ppm) Isobutanol (ppm) Isoamylalcohol (ppm)
Lower yeast pitching rate Ref. yeast pitching rate
Higher Alcohol
47
1.64
13.75
1.34 1.63
12.41
1.05
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
Acetaldehyde (ppm) Ethyl acetate (ppm) Isoamylacetate (ppm)
Lower yeast pitching rate Ref. yeast pitching rate
Aldehyde and Ester
48
Sensory Test Triangle test
Sample’s code Difference sample Correct Wrong Result
G/H/I G 8 0 Sig
Sample G : Trial 3 (Lower yeast pitching rate) Sample H&I : Trial 4 (Ref. yeast pitching rate)
Statistic for different test is triangle test at 95% significance. Panelists could detect difference of samples.
49
Lower Yeast Pitching Rate
Little higher pH in beer
Higher VDK during fermentation
Lower yeast cropping ratio and higher dead cell
More ester and Iso-amylalcohol
Sensory test is difference 50
Lactic acid Addition
Overview
Brew house part
Fermentation part
51
Trial 3 : Lower yeast pitching rate Trial 4 : Ref. yeast pitching rate
Yeast pitching rate
Summary
Lactic acid Addition
Yeast pitching rate 1.5 x 106 cells/%Plato/mlCW
52
Brew house part
Fermentation part
53