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Rules, Standards & Procedures

Brewing Process Equipment Standard

YEAST PROPAGATION & YEAST MANAGEMENT 1. INTRODUCTION

2

2. QUICK FLOW

2

3. YEAST MANAGEMENT

3

3.1 BASIC DESIGN YEAST STORAGE PLANT 3.2 YEAST STORAGE CELLAR DISTRIBUTION 3.3 YEAST PITCHING

3 3 4

3.3.1 Consistency & dead cell Measurement 3.3.2 Pitching rate Measurement 3.3.3 Yeast Dosing line

4 5 5

3.4 YEAST HARVEST & PURGE 3.4.1 Yeast Harvest line distribution 3.4.2 Number of harvest lines 3.4.3 Number of harvest to 1 YST 3.4.4 Yeast cooling 3.4.5 Yeast harvest control

3.5 YEAST STORAGE

7 8 8 8 9

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3.5.1 Number of yeast plants in case of multiple yest strains 3.5.2 YST Size 3.5.3 Number of YST 3.5.4 Yeast homogenisation method 3.5.5 Gas block or foam catcher 3.5.6 With or without carbon filter in air supply 3.5.7 Gas supply lines 3.5.8 YST cooling

3.6 WASTE YEAST PLANT

11 11 12 12 13 13 14 16

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3.6.1 Yeast In activation 3.6.2 Control of discharge

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4. YEAST PROPAGATION

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4.1 BASIC DESIGN YEAST PROPAGATION PLANT 4.2 DRIED YEAST OR CULTURE YEAST 4.3 INTAKE OF COLD- OR HOT WORT 4.4 REHYDRATION OF YEAST 4.5 PROPAGATION 4.5.1 Propagator size 4.5.2 Mixing in the propagator 4.5.3 Aeration of the propagator 4.5.4 Non aerated steps in F(S)T or One brew fermentor 4.5.5 Propagator cooling

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Yeast Propagation & Yeast Management Date: April 2008 Issue: 05

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Rules, Standards & Procedures

Brewing Process Equipment Standard 1. INTRODUCTION 2. QUICK FLOW

Yeast Propagation & Yeast Management --- Not recommended ---

Yeast pitching Swing bend execution dosing line With proximity switches Microscopic cell count

--- Add ons ---

--- Basic execution ---

Laboratory consistency & dead cell measurement

Automatic execution with mix proof valves Laboratory Thoma cell counter & dead cell measurement Aber yeast monitor

Volumetric flow measurement in dosing line

More than one dosing line

One dosing line CIP dosing line together with wortline Yeast harvest Swing bend execution dosing line

With proximity switches 1 harvest line 1 harvest to 2 YST

1 harvest to 1 YST Inline cooling in harvest line Volumetric flow measurement & Visual detection yeast/beer

Separate CIP of dosing line

Automatic execution with mix proof valves 2nd harvest/purge line directly to the WYT 1 harvest to 2 YST Deep cooling in the YST Turbidity measurement for detection yeast/beer Density measurement for detection yeast/beer Small purge based on volume only

Every yeast strain its own yeast plant >3 YST Stirrer

Gas block Without carbon filter in air supply

Iso-mix (pm) Foam catcher With carbon filter in air supply

Without steaming faciilities in aeration

Waste Yeast Handling 1 WYT No yeast inactivation Local controlled manual discharge of the WYT

Mixing using a stirrer or pumping system

Weighing cells YST More than one dosing line

Yeast Storage One yeast plant in case of muliple yeast strains 3 YST Homogenisation using a circulation pump

Cooling to maintain storage temperature

Sterile wort intake

Mass flow measurement in dosing line

Yeast rehydration Dried yeast Cold wort intake Rehydration using a Carlsberg Flask

With steaming facilities in aeration Deep cooling in the YST

> 1 WYT Inactivation by heat Chemical inactivation Automatic discharge of the WYT

Pure Culture Yeast Hot wort intake Rehydration using a rehydrator Initial propagation of pure culture yeast using a Carlsberg Flask

Yeast propagation Mixing by aeration Aerated steps in propagator

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Rules, Standards & Procedures

Brewing Process Equipment Standard 3. YEAST MANAGEMENT 3.1 BASIC DESIGN YEAST STORAGE PLANT Picture 3.1.1 Basic design yeast plant (functionality only) Sterile air

YEAST STORAGE TANKS

CIP

Free Air

Head space 50% Pressure Regulation

Inlet on max liquid level

Coolant

Waste Yeast Tank

FST

To lorry

FE YEAST COOLER Brewhouse

CIP Return CIP dosing line together with wortline

FE To FS or FST’s

Yeast harvest: • Swing bend/flow plate execution of the cellar distribution (not indicated in picture above) • Positive displacement pump as driving force for the yeast transfer from FST to yeast storage • Flow measurement for pre- and post run activities • Sight glass to detect beer/yeast transition • Yeast deep cooler to cool the yeast from FST harvest temperature until < 2 ºC • 1 harvest line to the yeast storage and waste yeast • Centrifugal pump to empty Yeast storage tanks to the waste yeast tank Yeast storage and pitching: • Three yeast storage tanks • Tank cooling to maintain storage temperature • Yeast homogenisation using a positive displacement pump and a recycle line • Prevent foaming o 50 % headspace o Pre-pressurise YST before harvest (pressure as low as possible) • 1 yeast dosing line (pitching) • Yeast dosing based on a mass flow measurement and laboratory consistency and dead cell measurement • CIP dosing line together with the wort line Waste Yeast plant • One Waste Yeast Tank • No yeast inactivation • Local controlled manual discharge of the WYT

3.2 YEAST STORAGE CELLAR DISTRIBUTION For investment costs reasons, the basic design for a yeast cellar is the flow plate (swing bend) execution. For quality reasons or in case of high operational costs (labour), a fully automated cellar (mix proof valves) can be considered.

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Rules, Standards & Procedures

Brewing Process Equipment Standard Some breweries are using proximity switches in combination with a flow plate execution. This set up is not recommended due to the following reasons”: • High investment costs (equipment, automation) • Reliability (regularly break down) • Equal procedures as for flow plate execution without proximity switches (to meet SHE requirements) The choice between the different distribution methods will be described in detail in the BDM Tank room.

3.3 YEAST PITCHING Yeast dosing is part of the wort transfer from whirlpool to the fermenting tank. All the yeast necessary for a full fermenting tank is dosed in the first brew.

3.3.1 CONSISTENCY & DEAD CELL MEASUREMENT Pitching rate should be based on yeast consistency measurement or if available a cell count using a Thoma/Coulter counter, all corrected for the dead cells percentage. A cell count using a microscope is not recommended since it is not accurate enough. This can be done using batch wise sampling and laboratory measurement, or inline measurement using a (Aber) yeast monitor during dosing. Yeast consistency can also be measured using the density measurement of a mass flow meter. The basic solution is based on batch sampling and laboratory measurement. Depending on the local labour costs or requested quality, the yeast monitor can be considered. Table 3.3.1.1: Overview consistency & dead cell measurement choice Item Basic Design Add on Add On Laboratory Laboratory Inline consistency measurement using a (Aber) Measurement Thoma Cell counter yeast Monitor Technical ++ + -Technologica + + ++ l Operational + Legend:

++ + 0 --

= = = = =

Add On Consistency measurement by density using density measurement of mass flow meter + + +

excellent good average mediocre poor

Technical: • Low investment costs for the basic solution • A Thoma cell counter is more expensive than laboratory consistency mesurement • A yeast monitor measurement is expensive compared to relatively simple laboratory equipment and batch sampling. A yeast monitor measures consistency and yeast viability • An additional density measurement to the mass flow meter (to measure consistency) is slightly more expensive. It does not measure yeast viability Technological: • Inline consistency measurement is independent of homogeneity. • Inline measurement measures each dosing, batch sampling only once and therefore storage time dependent. • Additional density measurement of the mass flow meter still requires laboratory dead cell measurement. In case of good yeast management, dead cell level is not very fluctuating. If fluctuation is low, not every batch needs to be measured.

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Rules, Standards & Procedures

Brewing Process Equipment Standard Operational: • In case of inline measurement only occasional calibration measurements instead of measuring each batch in case of laboratory measurements (labour costs) • In case of good yeast management, dead cell level is not very fluctuating. If fluctuation is low, not every batch needs to be measured.

3.3.2 PITCHING RATE MEASUREMENT The pitching rate can be measured using inline mass flow measurement or by the decrease of weight of the content of the yeast storage tank. (YST) The basic solution is based on inline volumetric flow measurement. Table 3.3.2.1: Overview pitching rate measurement Item Basic Design Add on Volumetric flow Inline Mass flow Measurement Measurement Technical ++ + Technologica + l Operational + + ` Legend:

++ + 0 --

= = = = =

Add On Weight decrease YST -

excellent good average mediocre poor

Technical: • Low investment costs for the basic solution o Mass flow measurement is more expensive o Only one inline measurement compared to weighing cells on each YST. Technological: • Weighing cell accuracy less than mass or volumetric flow measurement • No correction for yeast concentration in case of concentration gradients for volumetric flow measurement Operational: • More equipment to maintain in case of weighing cells

3.3.3 YEAST DOSING LINE 3.3.3.1 NUMBER OF YEAST DOSING LINES: The number of dosing lines is depending on the occupation of the dosing line. The basic design is based on only 1 dosing line. In practice it is proven that single yeast breweries up to a yearly capacity of 11.000.000 hl/year can run with only one dosing line. Even for a brewery with multiple yeast strains it is not recommended to use more than one dosing line. With a proper CIP philosophy (in compliance with the BDM CIP, cleaning before each dosing) only one dosing line is sufficient. Only in case more than 16 tanks per day need to be pitches a second dosing line can be considered. Calculation: Pitching time : 45 minutes Total CIP time : 45 minutes

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Rules, Standards & Procedures

Brewing Process Equipment Standard Number of dosings possible per 24 h: 16 dosing actions/day

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Rules, Standards & Procedures

Brewing Process Equipment Standard 3.3.3.2 CIP YEAST DOSING LINE The yeast dosing line can be cleaned together with the wortline or separately. The basic design is cleaning together with the wortline. Table 3.3.3.2.1: Choice cleaning the dosing line together with the wortline or separately. Item Basic Design Add On CIP together with Separate CIP of dosing wortline line Technical + Operationa 0 ++ l Legend:

++ + 0 --

= = = = =

excellent good average mediocre poor

Technical: • Low investment costs for the basic solution o No additional valves, piping and CIP program in case of cleaning together with the wortline. Operational: • Operational consequence of the basic solution is: o CIP only possible in case of FST switch • Flexibility problems can occurs in case of: o More than 1 brewhouse (2 or more dosing at the same time o Multiple yeast strains (CIP required) o In case of a lot of small fermenting tanks (many dosing/day)

3.4 YEAST HARVEST & PURGE The yeast is harvested from the fermentation storage tank to the yeast storage tank or waste yeast tank. In case the yeast quality is good in terms of generation, visual and microbiological condition, beer type and behavior during previous fermentation, the harvest will take place to the yeast storage tank. In case the yeast quality is insufficient in respect to the above-mentioned aspects, the harvest has to go to the waste yeast tank. To avoid foaming in the yeast storage tank several actions has to be taken. • First the temperature of the yeast must be lowered as soon as possible. The best way to do that is to cool the yeast using an inline cooler. • Secondly depending on the local circumstances it is sometimes necessary to harvest under a counter pressure. This counter pressure has to be as low as possible (max. 0.8bar) After the harvest this counter pressure has to be relieved slowly with care, but as fast as possible. • The last foam preventing action is to apply a headspace of 50 %. During fermentation, maturation and before emptying, the Fermenting Storage tank is purged (several times) to the waste yeast tank. For quality reasons it is also possible to transfer yeast from the yeast storage tank to the waste yeast tank.

3.4.1 YEAST HARVEST LINE DISTRIBUTION Basic design is a flow plate (swing bend) execution of the yeast distribution from fermenting cellar until the yeast storage tank. The stipulations concerning fully automatic (mix proof valves) execution and the use of proximity switches are the same as mentioned in Chapter 3.2

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Rules, Standards & Procedures

Brewing Process Equipment Standard 3.4.2 NUMBER OF HARVEST LINES The number of harvest lines depends on the number of FST’s. The basic design consists of 1 harvest line to the YST and WYT. Depending on the number of FST, an additional line to the Waste Yeast Tank (WYT) can be considered for harvesting or purging directly to the WYT Table 3.4.2.1. Choice number of harvest/purge lines Item Basic Design Add On 1 harvest line to YST & WYT Additional harvest/purge line to WYT Technical + Operationa < 36 tanks >36 tanks l Numb Legend:

++ + 0 --

= = = = =

excellent good average mediocre poor

Technical: • Low investment costs for the basic solution o Additional harvest and purge line without connection with the YST in case of an additional line. Operational: o Change over number of tanks depending on the process time. o 36 tanks is based on 18 days production time in FST. (Max. 3 harvest & 3 purge & 4 CIP/day)

3.4.3 NUMBER OF HARVEST TO 1 YST The basic design is based on 1 harvest to 1 FST. Mixing of yeast from several FST is not allowed. In case the YST is too small to harvest all to one YST, it can be considered to fill 2 YST’s with 1 harvest. To avoid (flocculence) differences between the 2 tanks, it is recommended to fill the YST’s alternating.

3.4.4 YEAST COOLING Yeast can be cooled in the YST or inline. It should be realised that cooling from harvest temperature to < 2 ºC in the tank is only applicable in case the YST is intensively mixed using for example a stirrer. If a inline cooler is installed, cooling of the yeast storage tank is still required to maintain storage temperature. For technical and technological reasons, the basic design is an inline cooler. Table 3.4.4.1. Choice yeast cooling Item Basic Add On Design Inline cooler Deep cooling in the YST Technical + -Technologica ++ l Operational + Legend:

++ + 0 --

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= = = = =

excellent good average mediocre poor

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Rules, Standards & Procedures

Brewing Process Equipment Standard Technical: • Low investment costs for the basic solution o Deep cooling in the YST requires a stirrer in each YST Technological: • Direct inline inactivation of yeast metabolism including CO2 production (temp: