Alle gjærkulturene vi kjøper startet vel egentlig fra 1 celle? Så svaret er vel ja?
Hvorfor må en ha en viss mengde med gjær?
- Trådstarter Zeek
- Startdato
Holmentoppen
Norbrygg-medlem
Veldig interessant tema. Denne artikkelen er en av de bedre jeg har sett. Peker bl.a. på konsekvensene av under- og overpitching: http://www.cara-online.com/blog/understanding-and-controlling-yeast-growth-in-the-brewery/
Holmentoppen
Norbrygg-medlem
Når WhiteLabs starter en nye produksjonsrunde, starter de med et utrolig lite antall. Hentes ut fra banken som ligger lagret i flytende nitrogen. Mener det er 10 celler, men kan hende jeg husker feil. Så stepper de opp 40 til 60 ganger. Den maksimale buddingen i en omgang er 5, såvidt jeg husker. Det er også grunnen til at man ikke kan lage en starter som mer enn femdobler antallet celler man hadde som utgangspunkt.
Klar over dette, men det har jo ingen likheter med hva vi gjør når vi brygger. De dumper ikke 10 celler ned i 25 liter vørter, lar det stå 2 uker, pakker og selger det. Oppdyrkning i lab er noe helt annet enn gjæring av vørter. Ja, celler spiser og formerer seg, men forholdene rundt denne prosessen er ikke de samme. Poenget mitt er i en diskusjon om brygging og gjæring, ikke mikrobiologi (eller hva det fagfeltet heter)
Holmentoppen
Norbrygg-medlem
Les artikkelen jeg postet en lenke til over her. Riktignok beregnet på større bryggerier, men grunnprinsippene er de samme. Det med Whitelabs var bare ment som et apropos til det med én celle.
Fin artikkel, men ser ikke at den sier noe om at underpitch ikke kan gi høyere FG. Men vi sporer uansett av. Det har kommet fram mye bra informasjon originaltemaet
Finn Berger
Moderator
Hvis ikke ølet er for sterkt (OG over 1.064) skulle ei pakke + litt risting holde lenge. Du må ikke rehydrere, heller.
Dette er ikke etter boka, men det funker. Det er i det hele tatt mye som funker
. En kollega brygger særs god IPA med OG på 1.070+ i 20-litersbatcher med ei pakke 05 strødd opp i dunken og litt frisk risting. (Jeg er pysete og rehydrerer når jeg bruker tørrgjær.) Men jeg sier ikke at det er å anbefale.
steinmb
Norbrygg-medlem
Å strø gjær i vørter er en effektiv måte å drepe og skade opp til 50% av tørrgjæren. Gjærcellene er skjøre etter tørking og trenger å re-hyrering i rent vann for å gjennopprettet membranene i celleveggen. Om en pakke tørrgjær inneholder ca. 120 milliarder gjærceller og man så dreper mange av disse på pitch + man kansje trenger kansje for 20-25L vørter, tja la oss si 450 milliarder celler så gjør man mye galt på en gang.
Man får øl men ikke optimalt og ikke uten bivirkninger og hvorfor ikke gjøre det beste ut av det når man tar seg bryet med å lage øl?
Man får øl men ikke optimalt og ikke uten bivirkninger og hvorfor ikke gjøre det beste ut av det når man tar seg bryet med å lage øl?
Jeg har gjort som du sier, rehydrert i vann, men ble anbefalt på den lokale bryggebutikken å rehydrere i vørteren. Om en skal rehydrere i vørteren ser jeg ikke helt poenget med å rehydrere, men kanskje noe jeg ikke har fått med meg?
Jeg er lat i dag og poster denne i sin helhet:
http://www.hbd.org/hbd/archive/3301.html#3301-4
Dan,
I appreciate your dilemma It is a universal problem for those that market
Active Dry Yeast.
Let me give you some facts regarding rehydration and you can decide for
yourself where you want to compromise.
Every strain of yeast has its own optimum rehydration temperature. All of
them range between 95 F to 105F. Most of them closer to 105F. The dried
yeast cell wall is fragile and it is the first few minutes (possibly
seconds) of rehydration that the warm temperature is critical while it is
reconstituting its cell wall structure.
As you drop the initial temperature of the water from 95 to 85 or 75 or 65F
the yeast leached out more and more of its insides damaging the each cell.
The yeast viability also drops proportionally. At 95 - 105 F, there is
100% recovery of the viable dry yeast. At 60F, there can be as much as 60%
dead cells.
The water should be tap water with the normal amount of hardness present.
The hardness is essential for good recovery. 250 -500 ppm hardness is
ideal. This means that deionized or distilled water should not be used.
Ideally, the warm rehydration water should contain about 0.5 - 1.0% yeast
extract
For the initial few minutes (perhaps seconds) of rehydration, the yeast
cell wall cannot differentiate what passes through the wall. Toxic
materials like sprays, hops, SO2 and sugars in high levels, that the yeast
normally can selectively keep from passing through its cell wall rush right
in and seriously damage the cells. The moment that the cell wall is
properly reconstituted, the yeast can then regulate what goes in and out of
the cell. That is why we hesitate to recommend rehydration in wort or
must. Very dilute wort seems to be OK.
We recommend that the rehydrated yeast be added to the wort within 30
minutes. We have built into each cell a large amount of glycogen and
trehalose that give the yeast a burst of energy to kick off the growth
cycle when it is in the wort. It is quickly used up if the yeast is
rehydrated for more than 30 minutes. There is no damage done here if it is
not immediatly add to the wort. You just do not get the added benefit of
that sudden burst of energy. We also recommend that you attemperate the
rehydrated yeast to with in 15F of the wort before adding to the wort.
Warm yeast into a cold wort will cause many of the yeast to produce petite
mutants that will never grow or ferment properly and will cause them to
produce H2S. The attemperation can take place over a very brief period by
adding, in encrements, a small amount of the cooler wort to the rehydrated
yeast.
Many times we find that warm water is added to a very cold container that
drops the rehydrating water below the desired temperature.
Sometimes refrigerated, very cold, dry yeast is added directly to the warm
water with out giving it time to come to room temperature. The initial
water intering the cell is then cool.
How do many beer and wine makers have successful fermentations when they
ignore all the above? I believe that it is just a numbers game. Each gram
of Active Dry Yeast contains about 20 billion live yeast cells. If you
slightly damage the cells, they have a remarkable ability to recover in the
rich wort. If you kill 60% of the cell you still have 8 billion cells per
gram that can go on to do the job at a slower rate.
The manufacturer of Active Dry Beer Yeast would be remiss if they offered
rehydration instructions that were less than the very best that their data
indicated.
One very important factor that the distributor and beer maker should keep
in mind is that Active Dry Yeast is dormant or inactive and not inert, so
keep refrigerated at all times. Do not store in a tin roofed warehouse
that becomes an oven or on a window sill that gets equally hot.
Active Dry Yeast looses about 20% of its activity in a year when it is
stored at 75 F and only 4% when refrigerated.
The above overview of rehydration should tell you that there is a very best
way to rehydrate. It should also tell you where you are safe in adapting
the rehydration procedure to fit your clients.
http://www.hbd.org/hbd/archive/3301.html#3301-4
Dan,
I appreciate your dilemma It is a universal problem for those that market
Active Dry Yeast.
Let me give you some facts regarding rehydration and you can decide for
yourself where you want to compromise.
Every strain of yeast has its own optimum rehydration temperature. All of
them range between 95 F to 105F. Most of them closer to 105F. The dried
yeast cell wall is fragile and it is the first few minutes (possibly
seconds) of rehydration that the warm temperature is critical while it is
reconstituting its cell wall structure.
As you drop the initial temperature of the water from 95 to 85 or 75 or 65F
the yeast leached out more and more of its insides damaging the each cell.
The yeast viability also drops proportionally. At 95 - 105 F, there is
100% recovery of the viable dry yeast. At 60F, there can be as much as 60%
dead cells.
The water should be tap water with the normal amount of hardness present.
The hardness is essential for good recovery. 250 -500 ppm hardness is
ideal. This means that deionized or distilled water should not be used.
Ideally, the warm rehydration water should contain about 0.5 - 1.0% yeast
extract
For the initial few minutes (perhaps seconds) of rehydration, the yeast
cell wall cannot differentiate what passes through the wall. Toxic
materials like sprays, hops, SO2 and sugars in high levels, that the yeast
normally can selectively keep from passing through its cell wall rush right
in and seriously damage the cells. The moment that the cell wall is
properly reconstituted, the yeast can then regulate what goes in and out of
the cell. That is why we hesitate to recommend rehydration in wort or
must. Very dilute wort seems to be OK.
We recommend that the rehydrated yeast be added to the wort within 30
minutes. We have built into each cell a large amount of glycogen and
trehalose that give the yeast a burst of energy to kick off the growth
cycle when it is in the wort. It is quickly used up if the yeast is
rehydrated for more than 30 minutes. There is no damage done here if it is
not immediatly add to the wort. You just do not get the added benefit of
that sudden burst of energy. We also recommend that you attemperate the
rehydrated yeast to with in 15F of the wort before adding to the wort.
Warm yeast into a cold wort will cause many of the yeast to produce petite
mutants that will never grow or ferment properly and will cause them to
produce H2S. The attemperation can take place over a very brief period by
adding, in encrements, a small amount of the cooler wort to the rehydrated
yeast.
Many times we find that warm water is added to a very cold container that
drops the rehydrating water below the desired temperature.
Sometimes refrigerated, very cold, dry yeast is added directly to the warm
water with out giving it time to come to room temperature. The initial
water intering the cell is then cool.
How do many beer and wine makers have successful fermentations when they
ignore all the above? I believe that it is just a numbers game. Each gram
of Active Dry Yeast contains about 20 billion live yeast cells. If you
slightly damage the cells, they have a remarkable ability to recover in the
rich wort. If you kill 60% of the cell you still have 8 billion cells per
gram that can go on to do the job at a slower rate.
The manufacturer of Active Dry Beer Yeast would be remiss if they offered
rehydration instructions that were less than the very best that their data
indicated.
One very important factor that the distributor and beer maker should keep
in mind is that Active Dry Yeast is dormant or inactive and not inert, so
keep refrigerated at all times. Do not store in a tin roofed warehouse
that becomes an oven or on a window sill that gets equally hot.
Active Dry Yeast looses about 20% of its activity in a year when it is
stored at 75 F and only 4% when refrigerated.
The above overview of rehydration should tell you that there is a very best
way to rehydrate. It should also tell you where you are safe in adapting
the rehydration procedure to fit your clients.
Finn Berger
Moderator
Rare greier, dette. Når du leser beskrivelsen av hva som skjer med de stakkars cellene når du mishandler dem på den måten noen gjør, framstår det jo som et rent mirakel at det kan bli øl - enn si godt øl. Og jeg vender tilbake til min 1 pose per brygg uten rehydrering-kamerat: Framgangsmåten hans svarer jo teoretisk til virkelig grov underpitching. Kanskje setter han i gang gjæringen med bare 1/3 av det antallet oppegående gjærceller som han burde ha. Så i det minste burde han få problemer med fusel! Men det får han altså ikke. Ølet hans er helt reint. Og jeg er temmelig følsom for stoffet.
Jeg tviler ikke på vitenskapen, men det er også vanskelig å tvile på at ølet til kameraten min er godt. OK, kanskje kunne en kresen gane peke på ting som kunne vært bedre. Men det er godt.
Jeg er ikke tilfreds, for jeg skjønner ikke. (Og som sagt; jeg tror ikke at det er dumt å rehydrere. Jeg rehydrerer.)
Jeg tviler ikke på vitenskapen, men det er også vanskelig å tvile på at ølet til kameraten min er godt. OK, kanskje kunne en kresen gane peke på ting som kunne vært bedre. Men det er godt.
Jeg er ikke tilfreds, for jeg skjønner ikke. (Og som sagt; jeg tror ikke at det er dumt å rehydrere. Jeg rehydrerer.)
gustavf
Administrator
Jeg tror, og jeg understrekter tror, at en del av grunnen er at gjæren tåler møte med vørter en del bedre enn en del artikler antyder. I tillegg kommer det at tallene for antall celler i ei pakke ikke er nøyaktig, så det blir en del usikkerhet. Sammenligner du dataarkene fra Safale, som er deres garanti til kundene sine, så stemmer de heller ikke med tall fra ymse kalkulatorer.
Finn Berger
Moderator
Det blir spekulasjon fra min side. Har du lite gjær kjører du en starter basert på en liten dose. Den gir gode vilkår for vekst med sukker og oksygen ( og litt gjærnæring). Så settes denne til vørteren og alt er vel. Min antagelse er at ressurser blir brukt opp i en vørter av normal størrelse. Oksygen brukes opp og også andre næringsstoffer. Dermed stopper veksten av antall gjærceller opp og utgjæringen må skje med den populasjonen som er oppnådd. Settes det til få gjærceller må mye av populasjonen bygges opp og næringsressursene i vørteren blir raskere tømt.
