8 votes
Accepted

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 ...
  • 1,759
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 ...
6 votes
Accepted

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 ...
  • 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 ...
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 ...
  • 36.2k
5 votes
Accepted

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 ...
  • 5,611
4 votes
Accepted

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 ...
4 votes
Accepted

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 ...
4 votes
Accepted

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'...
  • 1,152
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-...
  • 3,718
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 ...
  • 711
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 ...
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 ...
  • 10.1k
3 votes
Accepted

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 ...
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 ...
  • 10.1k
3 votes
Accepted

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 ...
  • 10.1k
3 votes
Accepted

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 ...
3 votes
Accepted

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 ...
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, ...
  • 328
3 votes
Accepted

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 ...
3 votes
Accepted

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 ...
  • 560
2 votes
Accepted

Can we use monoammonium phospate (MAP) as yeast nutrient for wine making?

Monoammonium phosphate and diammonium phosphate contain all the same chemical compounds (phosphate ions, ammonium ions, and hydrogen ions), the major difference is that MAP has a second hydrogen in ...
  • 165
2 votes
Accepted

Overflowing yeast starter

It is not unusual. I'd easily believe that a 1.5L starter would overfill a 2L erlenmeyer at full krausen. I would suggest using an anti-foam agent in the future. I regularly do 1.6L starters in a 2L ...
  • 10.1k
2 votes
Accepted

Is yeast cell count a constant function of starter size?

No, it is not true. The "yield factor" of yeast is a function of both the starter volume and the inoculation rate.
  • 10.1k
2 votes

How long should I expect to wait before seeing activity in my yeast starter?

Have you taken a gravity reading? I've had starters that have very little apparent activity that are fermenting right along. It can be tricky to take a gravity sample for a low-volume starter, but ...
  • 10.1k
2 votes

Starter wort volume = BEFORE or AFTER 10-15 minute boil

I don't know your calculator. No one here knows unless you will link to it. So we cannot tell what it's developers had in mind. That said, you want about 1.040 OG / 10 Blg after boil. If that means ...
  • 3,718
2 votes

Is these yeast starter calculation correct?

That is a small batch 2.43 gallons. I too show a yeast viability at 56% Your starter volume of 300ml seems low. That is more of a proofing volume. My calculator shows 107bil cell growth if you use ...
2 votes

Erlenmeyer flask rinsed in StarSan

With StarSan (really, with any no-rinse sanitizer), as long as you're using it at the prescribed dosage and draining your vessel well, there's absolutely no danger to your yeast. There would need to ...
2 votes
Accepted

Sour Starter From Dregs

This is a very broad question but here's some direction: ...and the usefulness of this answer depends on whether you are planning on starting a long term barrel project or a medium term sour beer or ...
  • 3,030
2 votes

Unwanted yeast flavor last 2 brews (using starter)

First thing, its not generally recommended or needed to make starters when using the dried yeast that you listed. That being said its not likely to super hurt you either. Its likely a combination of ...
  • 36.2k

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