[natebrews]

So with all the LODO talk that has been going around, there has been a lot about spunding.  This is something that I had tried to do for a while (without a blowoff valve, so kinda crude until recently) just to get the self carbonation and oxygen scrubbing from the transfer.

I often hear (ok, read) people saying that you should do it with a few gravity points left, basically what you would calculate as priming gravity points if I understand it correctly. 

My question is this:  How much does it matter when you transfer so long as there is more than enough sugar left in there to carbonate?  I could see not wanting to go too early just from a practical aspect of krausen getting in the blowoff valve and excessive junk in the keg, but what about transferring with 20 points left, or at 70% attenuation, or whatever?  Are there other deleterious effects to doing it at an earlier stage like that (so long as you have a pressure relief valve so the keg doesn't get too high in pressure)? 

[The Beerery]

So with all the LODO talk that has been going around, there has been a lot about spunding.  This is something that I had tried to do for a while (without a blowoff valve, so kinda crude until recently) just to get the self carbonation and oxygen scrubbing from the transfer.

I often hear (ok, read) people saying that you should do it with a few gravity points left, basically what you would calculate as priming gravity points if I understand it correctly. 

My question is this:  How much does it matter when you transfer so long as there is more than enough sugar left in there to carbonate?  I could see not wanting to go too early just from a practical aspect of krausen getting in the blowoff valve and excessive junk in the keg, but what about transferring with 20 points left, or at 70% attenuation, or whatever?  Are there other deleterious effects to doing it at an earlier stage like that (so long as you have a pressure relief valve so the keg doesn't get too high in pressure)?

I target 4 points left, maybe a little more (6) if its an ale since you will need ~30psi to carb. You want to get pretty close to that because you don't want to pull the yeast off the primary cake for as long as you can. It's true we are using the stragglers to carbonate, as most of the good yeast has fallen to the bottom. These guys won't have enough gas to bring it down much further than a few points. You also run into the issue of autolysis if you are pulling too much yeast over from the primary. It may not present itself as the typical nastiness, but it will certainly raise pH and cause some issues. So those are 2 of the glaring issues.

[natebrews]

Um...I only count 1 from your text (yeast autolysis of transferred yeast), but that is a good one.  Or was your first point that the yeast that caught up in the transfer will not be able to finish attenuating?  What do you think the time frame is on the autolysis?

I mainly ask because I'm not always able to be there to do transfers when "the time is right".  Especially for the low gravity stuff that I often brew (3.5% to 4%), the stuff passes through those attenuations while I'm at work, or asleep or fighting with little children.  Not so much with the lagers, as they are chugging along slower but with an english ale the whole ferment time might be 2.5 days so the window is pretty short.

[The Beerery]

Um...I only count 1 from your text (yeast autolysis of transferred yeast), but that is a good one.  Or was your first point that the yeast that caught up in the transfer will not be able to finish attenuating?  What do you think the time frame is on the autolysis?

I mainly ask because I'm not always able to be there to do transfers when "the time is right".  Especially for the low gravity stuff that I often brew (3.5% to 4%), the stuff passes through those attenuations while I'm at work, or asleep or fighting with little children.  Not so much with the lagers, as they are chugging along slower but with an english ale the whole ferment time might be 2.5 days so the window is pretty short.

First was attenuation, second was autolysis.

I would always err on not enough, and prime with sugar if you miss it.

[Phil_M]

When I casked an ale recently I racked about 2 points higher than the FFT, and added sugar as well.

I can't adopt all the low O₂ methods yet, but I'm likely to start spunding all my beers. I know have proof that the beers that I carbonate naturally oxidize far more slowly than those that are force carbed.