8 votes
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Will reused yeast change beer taste?

we can get away with re-using yeast, because Mutation isn't instantaneous, it take multiple generations to change a whole batches properties. Also bigger brewers use a "mother culture" to grow more ...
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  • 1,759
7 votes
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Saving a yeast starter

The starter is still good in that time. Very roughly, a 2L starter, presumably from a vial or smack pack, probably netted you between 200bn and 400bn cells. If you used 3/4 of it, you probably have 50-...
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  • 10.1k
7 votes

Storing mason jars of wort, for yeast starters, at room temperature

Without pressure canning, unfermented wort doesn't have a low enough pH to be shelf stable. From The Maltose Falcons website: The process is almost identical to the one that you or your family may ...
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6 votes
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What does a gravity reading really mean?

Specific gravity measures density, which is mass/volume. If you measured the total mass of your system (3000g + 300g) you would have gotten 3300 grams, but the volume is not 3000 ml because you added ...
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  • 344
6 votes

Production of yeast

Almost certainly the starter yeast is yeast slurry that's been stored frozen in liquid nitrogen. Interestingly, one of the most common methods is to store it inside sealed-off portions of plastic ...
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5 votes

Storing mason jars of wort, for yeast starters, at room temperature

Sanitation is not sterilization. You might find a couple jars out of a batch last longer than others. But the only way to be sure is to buy a pressure canner. They are relatively cheap and can be ...
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  • 36.2k
5 votes
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Why does Northern Brewer's Fast Pitch Canned Wort not require any boiling?

Malt extract does not need to be boiled to make beer. It is perfectly possible to make beer using extract and cold water although it s a little easier if you dissolve the extract in boiling water ...
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  • 5,626
4 votes
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2 yeast starts with one stir plate

That sounds like a plan. When the starter is cool the yeast will sediment quicker so you can pour off the spent wort easier. Definitely take yeast out of the fridge on brewday, let it warm. If you ...
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  • 27k
4 votes
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Gross layer of foam at the end of fermentation and aging

I get the same kraeusen when using liquid yeast - it's not from hydration shock. In fact, the dead yeast that don't survive hydration simply fall to the bottom of the fermentor. The reason for the ...
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  • 27k
4 votes
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Why toss the starter wort?

It is recommended to decant and dispose of the starter beer because the starter beer is nasty and oxidized, nasty and devoid of fermentable sugar by the time the yeast have reproduced to pitching ...
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  • 2,947
4 votes
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If oxygen is important mostly during the lag phase why not pre-oxygenate the yeast pitch prior to inoculation?

Strictly speaking, as long as you can ensure adequate and even oxygen contact with all of the yeast cells (a hard task, given the viscosity of yeast slurry), and provided the oxygenation comes ...
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4 votes
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My first yeast starter with a stir plate, possibly a disaster

Smack packs contain yeast nutrients, and sugars nothing magical. Its just a mini starter in a bag for proofing yeast for direct pitching. Don't need it at all If doing your own starter. If you do all ...
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4 votes
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Should a yeast starter be kept in the dark?

According to Beer Advocate, This is when the beer has been exposed to ultraviolet light for a period of time. Hop-derived molecules, called isohumulones, are basically ripped apart. So unless you'...
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  • 1,142
4 votes

What's the best method of storing yeast for 4 to 6 months in the refrigerator?

Just do it Nothing you described is needed or beneficial with modern liquid yeast packages. For example Weast's Activator: The Activator™ package was designed with superior UV light- and oxygen-...
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  • 3,706
4 votes

Alternative to stir plate for yeast starter (and erlenmeyer flask)

I use a 750 ml bottle, sanitised aluminium foil and a rubber band. Keep aerated by stirring it gently, occasionally during the first 12h; I stir every 6th hour or so. After 18-48h I use it or ...
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  • 711
3 votes

If oxygen is important mostly during the lag phase why not pre-oxygenate the yeast pitch prior to inoculation?

There's only so much oxygen that the N-hundred billion cells that you pitch can "hold". As well, there's only so much oxygen that can be diffused into the liquid containing those cells. And not only ...
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  • 10.1k
3 votes
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Two yeast packs in one starter?

Increasing the innoculation rate alone will not necessarily result in a linear increase in cells. You'll have twice as many cells now competing for the same amount of sugars and nutrients, they may ...
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  • 10.1k
3 votes

yeast starter, always a good addition?

It's almost always a good idea. Pitching the right amount of healthy, active yeast is one of the easiest and most important things you can do. This is especially true for high-gravity beer, which is ...
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3 votes
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How long to refrigerate yeast starter before pitching into wort?

Ideally, you want the liquid portion of the starter to be crystal clear, meaning no yeast is left in suspension. In this scenario, you carefully pour the liquid off the sediment, leaving a enough to ...
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  • 8,978
3 votes

Is these yeast starter calculation correct?

Yes, it roughly lines up using my preferred calculator if I use the stir-plate aeration options (the "C.White" option has 124 bn cells, "Kai" has 95 bn cells). I'll note that the Brewer's Friend ...
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  • 10.1k
3 votes

Should a yeast starter be kept in the dark?

Really depends if you use hops or not. I always put a few pellets in for thier antimictobial properties. And it depends when and how you pitch your starters. Light + hops would be bad If your ...
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3 votes
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Starter wort volume = BEFORE or AFTER 10-15 minute boil

Yes, starter calculators are a post boil volume. Your boil off depends on what you're boiling in (surface area mainly) and how hot you boil it. Do a test to see how much your vessel and burner ...
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3 votes
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Risks of pitching a high gravity starter?

Just cold crash the starter, decant the beer off and pitch the yeast slurry. The main function of a starter is to grow yeast to a proper cell count for your batch. It's actually pretty hard to over ...
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3 votes
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Simulating a yeast starter for fine tuning a stir plate

I haven't noticed any difference in the performance of my home-built stir plate between water and wort/yeast with one exception. I often make two-stage starters and refrigerate the flask between ...
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3 votes

Cell growth factors in different types of yeast starter

If you're comfortable doing the math yourself you could use some bioreactor equations to model the yeast growth. I would start with the assumption that growth is limited by initial population, ...
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  • 328
3 votes
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Really fast attenuation with starter. Is this to be expected

Yes it's totally possible. But I would expect a lower OG than you estimate. 1.071 is possible to drop out that quick but not very likely. Take a hydrometer AND refractometer reading on the finished ...
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3 votes
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Why is a yeast starter necessary? How is it different than standard fermentation?

The point of a starter is to obtain a higher and healthier yeast count before you pitch into the wort. This is accomplished because the 100g of DME/Liter create enough sugar for the yeast to reproduce ...
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  • 560
2 votes
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Is a yeast starter required for this recipe

OK, a couple things. One, don't make a starter for dry yeast. It has many more cells than liquid so a starter isn't needed. In addition, dry yeast is coated with a nutrient and if you make a ...
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  • 33.3k
2 votes
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Proposed yeast starter

1/2 gallon (~1900mL) will probably net you about 350bn cells (if you have a stir plate, yeast isn't too old, &c.). For 100L of ~1.040 wort, you want closer to 750bn cells (depending on gravity, ...
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  • 10.1k
2 votes

yeast starter, always a good addition?

The conventional wisdom is to use starters, per the other answers here. I won't argue with that--there's certainly no harm in pitching a lot of healthy yeast. That said, I've gotten very good ...
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  • 1,103

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