# Vacuum splash rack & oxidation



## tonyt (Jul 5, 2012)

I usually splash rack all my wine each time I rack thinking that it will help drive off any gas that might still be left in the wine. Then I was reading an article about keeping air (oxygen) away from wine in every step. So if I splash rack into a carboy under vacuum should I worry about oxidation?


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## Rocky (Jul 5, 2012)

Tony, I splash rack at just about every opportunity and I do not worry about O2 because the exposure is for such a short period of time and then I fill the carboy to within an inch or two of the stopper. I think if one works fast there would be no problem.


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## ibglowin (Jul 5, 2012)

If its a white wine I try hard to keep it to a minimum. It its a red wine these days I say bring on the oxidation (within reason of course).


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## SBWs (Jul 5, 2012)

If you are under a vacuum there is little to no air in the carboy to cause oxidation. What you have in there is co2 being pulled from the wine.


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## tonyt (Jul 5, 2012)

SBWs said:


> If you are under a vacuum there is little to no air in the carboy to cause oxidation. What you have in there is co2 being pulled from the wine.


That's kind of what I was thinking but wanted y'all to weigh in.


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## vacuumpumpman (Jul 5, 2012)

SBWs said:


> If you are under a vacuum there is little to no air in the carboy to cause oxidation. What you have in there is co2 being pulled from the wine.


 
That is a very good explanation of it - I will typically always splash rack under vacuum. I takes about 4 minutes to transfer 6 gallons of wine.


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## JohnT (Jul 6, 2012)

Ask yourself this.... If you splash rack every time, and you have made several batches of wine, how many of those batches have oxidized?

The risk of oxidation is mostly dependent on the PH level and the amount of tannins in your wine. As long as these two level are where they should be, you should have a very low risk of oxidation when splash racking. 

Even though there is minimal risk, I splash rack when needed (when I have hydrogensulfide issues) and do just a standard racking otherwise.

johnT.


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## Lurker (Jul 6, 2012)

If you mean to allow the wine to fall into the carboy while vacuum racking, I've been doing it for a few years with no ill effects. I do give it a final shake before bottling to get out the last bit of gas but that is one of the benefits of vacuum racking.


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## fafrd (Apr 20, 2017)

SBWs said:


> *If you are under a vacuum there is little to no air in the carboy to cause oxidation. *What you have in there is co2 being pulled from the wine.



If this is correct, it should be true when bottling under vacuum as well, no?

I see that most/all of the commercial vacuum bottling systems divert the incoming wine to the sides of the bottle rather than letting it splash straight to the bottom.

If this is merely to reduce the amount of foaming, I get it, but most of them clain that it avoids oxidation and is 'gentler' on the wine.

Is there any benefit to filling down the side of the bottle under vacuum rather than splashing straight down or is it just done to minimize foaming!


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## vacuumpumpman (Apr 20, 2017)

The allinonewinepump was designed to be under vacuum and go down the side of the bottle to prevent any foam from agitation of the wine, or any left over CO2. 
I now have a precision vacuum release valve which aids in this process by adjusting the vacuum even lower while bottling and keeping better flow control.


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## Johnd (Apr 20, 2017)

If your wine is still releasing CO2 as you are bottling, unless you intend carbonated wine, your wine is not ready to bottle.


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## fafrd (Apr 20, 2017)

vacuumpumpman said:


> The allinonewinepump was designed to be under vacuum and *go down the side of the bottle to prevent any foam from agitation of the wine, or any left over CO2. *
> I now have a precision vacuum release valve which aids in this process by adjusting the vacuum even lower while bottling and keeping better flow control.



I agree with the comment that if your wine is still releasing CO2, it is probably not ready to be bottled, but even if you want the potential of further CO2 release under vacuum during bottling, that would be an argument in favor of 'splash bottling' (a stream straight to the bottom) rather than 'going down the side'.

So why is splash bottling harmful to the wine? Is it the increased 'agitation' that is harmful? Is it increased oxidation (under vacuum)? Is it increased foaming?

If it is primarily increased foaming that is the concern, is the formation of foam itself harmful to the wine or that increased foam can result in inconsistent fill height?


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## DoctorCAD (Apr 20, 2017)

Thin film degassing...that's the reason for running down the side. The wine spreads out and gives a huge increase in surface area for the vacuum to "work" on.


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## fafrd (Apr 21, 2017)

DoctorCAD said:


> Thin film degassing...that's the reason for running down the side. The wine spreads out and gives a huge increase in surface area for the vacuum to "work" on.



I hear 'ya, but that means the reason to bottle 'down the side' is to promote further degassing, and if the wine is already sufficiently degassed prior to bottling, there is no advantage to 'down-the-side' bottling under vacuum over splash-bottling.

If your wine is already sufficiently degassed, and if you are bottling under vacuum where oxidation should be less of a concern, I'm trying to nail down whether there is any subatantive disadvantage/drawback to splash-bottling over 'down-the-side' bottling.


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## Mismost (Apr 21, 2017)

fafrd said:


> I hear 'ya, but that means the reason to bottle 'down the side' is to promote further degassing, and if the wine is already sufficiently degassed prior to bottling, there is no advantage to 'down-the-side' bottling under vacuum over splash-bottling.
> 
> If your wine is already sufficiently degassed, and if you are bottling under vacuum where oxidation should be less of a concern, I'm trying to nail down whether there is any subatantive disadvantage/drawback to splash-bottling over 'down-the-side' bottling.



yes there is....down the side produces much less foaming when bottling, which in my mind, is reason enough.


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## Johny99 (Apr 21, 2017)

Remember that a vacuum is simply lower than ambient pressure. Depending on your pump, there is air and thus oxygen in the bottle or carboy. So while there would be less air and thus oxygen entrainment under vacuum, it isn't zero. So splash racking into a vacuum will entrain more air than a laminar flow down the side. It is the presence of gas pressure under the film of wine that creates foam.


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## fafrd (Apr 21, 2017)

Mismost said:


> yes there is....down the side produces much less foaming when bottling, which in my mind, is reason enough.



Foaming is bad if it results in inconsistent fill height, but does it cause any issues other than that?


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## fafrd (Apr 21, 2017)

Johny99 said:


> Remember that a vacuum is simply lower than ambient pressure. Depending on your pump, there is air and thus oxygen in the bottle or carboy. So while there would be less air and thus oxygen entrainment under vacuum, it isn't zero. So splash racking into a vacuum will entrain more air than a laminar flow down the side. It is the presence of gas pressure under the film of wine that creates foam.



I agree, most home vacuum systems seem to reduce pressure to somewhere between 1/2 to 1/3 of ambient, and this ought to mean that the amount of oxidation you get when splashing in such a partial vacuum is ~1/3 - 1/2 of what you'd get splash-racking/bottling under siphon, right? 

So is that the reason a laminar flow down the side is preferable, under partial vacuum or not? Is oxidation during bottling the issue you are trying to avoid?


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## Johny99 (Apr 21, 2017)

It is the one I try to avoid. I've never really grasped the "bruise" the wine issue, or at least ever had it explained to me.


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## vacuumpumpman (Apr 21, 2017)

I agree with alot of the statements above - 

Take any bottle of wine that is corked - commercial or homemade and shake it up . You will see foam inside the bottle - That is exactly what is happening as you fill your bottle. I like to keep all my liquid levels very consistent.

There are alot of people who bottle their wine too early and will get some CO2 out when bottling - but mainly I believe it is just agitation of the wine - so going down the side helps prevent this.


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## fafrd (Apr 21, 2017)

Johny99 said:


> It is the one I try to avoid. I've never really grasped the "bruise" the wine issue, or at least ever had it explained to me.



OK, so I think you are agreeing with me that until someone explains how agitating/splashing wine 'bruises it' there may be no advantage to avoiding splash bottling other than possibly reducing oxidation during bottling.

Now on the subject of oxidation while bottling under partial vacuum, there are only two possibilities: either oxidation is not a concern under partial vacuum because there is insufficient oxygen present under partial vacuum to cause any meaningful degree of oxidation during the short period of time before the bottle is filled (as many claim), or oxidation can be a problem despite the partial vacuum.

For the first case that oxidation can't be problem under partial vacuum during the ~20-30s until the bottle is filled, there is really no advantage to avoiding splash bottling.

For the second case that oxidation is a concern when bottling under partial vacuum, it's not clear to me that 'down-the-side' flow is better than splash-bottling. When you want aeration/oxidation during transfer, such as at the first racking, many of the textbooks instruct you to do that by transferring down the side of the carboy, rather than by splash-transferring.

So if you are trying to avoid oxidation during bottling under partial vacuum, it's not at all clear to me that 'down-the-side' flow is preferable to splash bottling.

'Up-from-the-bottom' bottling, such as you get with a bottling wand, is pretty clearly the best flow to avoid oxidation during bottling, but pretty much no one goes to the trouble of trying to bottle up from the bottom with a vacuum pump.

So while I agree that oxidation under partial vacuum may be more of a concern than most admit, I'm not sure 'down-the-side' is better than splash bottling to reduce the level of possible oxidation...


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## fafrd (Apr 21, 2017)

vacuumpumpman said:


> I agree with alot of the statements above -



It would help to have clarity on which of the above statements you are in agreement with.



> Take any bottle of wine that is corked - commercial or homemade and shake it up . You will see foam inside the bottle - That is exactly what is happening as you fill your bottle. I like to keep all my liquid levels very consistent.



OK, so I think you are confirming that foam created while bottling can interfere with achieving a consistent fill level when bottling under vacuum. That makes sense and all by itself may be sufficient reason to reduce/avoid foaming by bottling down the side rather than splash bottling. But it has nothing to do with being 'better for the wine', and if you have a way to assure consistent fill level despite foaming, there is no reason to avoid splash bottling.



> There are alot of people who bottle their wine too early and will get some CO2 out when bottling - but mainly I believe it is just agitation of the wine - so going down the side helps prevent this.



This may be true, but it is another point. If you are not bottling your wine too early and are not interested in achieving additional outgassing during bottling, it does not apply to you and the only reason to avoid splash bottling is if it allows you to deliver a more consistent fill level.

If you do want to outgass while bottling, then that might be a reason 'down-the-side' bottling is better than splash bottling, though splash bottling should also achieve a far higher degree of outgassing than 'up-from-the-bottom' bottling.

Recapping both of these last two posts, it seems to me that oxidation and outgassing are related. A gentle transfer that minimizes oxidation should also minimize outgassing. A violent or 'microlayer' transfer than maximizes outgassing should also maximize the possibility of oxidation. If I am incorrect about this, I would greatly appreciate having it explained to me.

But assuming that understanding is correct, if 'down-the-side' bottling is best for outgassing, it should also be worst for potential oxidation.

So if you are not concerned about oxidation when bottling under partial vacuum and have no need of additional outgassing, the only reason to prefer 'down-the-side' bottling to splash bottling is that it reduces foaming which may make it easier to deliver a consistent fill level.

But if you are concerned about oxidation when bottling under partial vacuum, have no need of additional outgassing, and are able to deliver a consistent fill level despite the presence if increased foam, splash bottling should at least as good if not better than 'down-the-side' bottling.

I think I fall into this latter camp and am trying to understand whether there are any downsides I have overlooked before going down the 'splash-bottling-under-vacuum' route...


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## stickman (Apr 21, 2017)

I believe that down the side is more gentle, splash bottling creates more turbulence and mixing, which may increase the oxygen pick-up of the wine. Oxygen is being picked up by the wine regardless of vacuum or not, maybe slightly less under vacuum; this is much less concern for tannic reds, more of a concern for whites. The main issue is having enough sulfite in the wine to react with the acetaldehyde and other compounds that will be generated as a result of the increased oxygen.


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## vacuumpumpman (Apr 21, 2017)

@ fafrd

Building a system like you want is a bit more difficult to use - than what I am selling - 

Your fill tube will be approx 12'' long and you will have to use vacuum to get your level height, by sucking off the excess wine into a vacuum reservoir. 

You will have alot more wine in your catch container than I did - approx 1-2 tablespoons for the last 133 bottles I just did last weekend.
http://www.winemakingtalk.com/forum/showthread.php?t=56531

Also when you pull out your fill tube that is 12'' long will now bring down your liquid height because of the displacement of the fill tube.

I think it might be quite awkward to go from bottle to bottle,and without dripping. 

I believe instead of talking about it - you should put it in practical use and let us know your results - I already tried it - but it is always best to try things on your own.


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## fafrd (Apr 21, 2017)

stickman said:


> I believe that down the side is more gentle, *splash bottling creates more turbulence and mixing, which may increase the oxygen pick-up of the wine*. Oxygen is being picked up by the wine regardless of vacuum or not, maybe slightly less under vacuum; this is much less concern for tannic reds, more of a concern for whites. The main issue is having enough sulfite in the wine to react with the acetaldehyde and other compounds that will be generated as a result of the increased oxygen.



Appreciate your input, and especially the difference between whites and reds.

My main concern is reds, and while I agree oxygen is probably being picked up even in a partial vacuum, I'm still questioning whether splash bottling/racking increases oxidation compared to 'down-the-side' / microlayer bottling/racking.

If this was so, then why woukd most references recommend 'down-the-side' / microlayer racking of carboys when oxygenation is desired, rather than splash-racking?

You are correct that oxygenation is less of a concern for tannic reds, and especially if properly protected by free-SO2, so the question is probably largely irrelevant in that case, but I'm still interested to understand whether splash bottling / racking is actually worse (when trying to avoid oxidation) than down-the-side / microlayer bottling / racking.


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## fafrd (Apr 21, 2017)

vacuumpumpman said:


> @ fafrd
> 
> Building a system like you want is a bit more difficult to use - than what I am selling -
> 
> *Your fill tube will be approx 12'' long* and you will have to use vacuum to get your level height, by sucking off the excess wine into a vacuum reservoir.



No, I'm not trying to build a fill system involving bottom-up filling under vacuum. Appealing but next to impossible for all the reasons you've outlined.



> You will have alot more wine in your catch container than I did - approx 1-2 tablespoons for the last 133 bottles I just did last weekend.
> http://www.winemakingtalk.com/forum/showthread.php?t=56531



Very impressive! I assume that when you were bottling, the other of you were manning the corker - what % of the 2-1/2 hours was spent on bottling/corking?



> Also when you pull out your fill tube that is 12'' long will now bring down your liquid height because of the displacement of the fill tube.
> 
> I think it might be quite awkward to go from bottle to bottle,and without dripping.



As I said, I'm not interested to try bottom-up filling under vacuum. I am interested in understanding whether splash-bottling under vacuum is truly worse than down-the-side bottling under vacuum (for heavy reds).



> I believe instead of talking about it - you should put it in practical use and let us know your results - I already tried it - but it is always best to try things on your own.



As I said, I'm not interested to try bottom-up filling under vacuum. I am interested in understanding whether splash-bottling under vacuum is truly worse than down-the-side bottling under vacuum (for heavy reds).

Practical use won't be before September, so just trying to learn/experiment for now...

If/when I make any experiments of splash bottling versus down-the-side bottling, I'll report back. Of course, in terms of assessing the impact on wine, it might be a year or two before any differences become evident .


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## vacuumpumpman (Apr 21, 2017)

@ fafrd
I was assuming that you wanted to fill from the bottom according to one of your comments, my mistake.

I can fill a 750 ml bottle of wine under vacuum in approx 15 seconds, using the Allinonewinepump being that it is under vacuum - and air is made up of 21% of oxygen. I know for certain that there is less contact with oxygen due to the bottle being under vacuum.Especially considering I sulfite them and turn them upright as soon as I am ready to bottle.

I personally don't think how you fill a bottle under vacuum will have that much effect - to oxidize your wine, only better liquid height and less foaming.


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## stickman (Apr 21, 2017)

At this point, any discussion of what method would supply more oxygen to the wine is just speculation or theory. The amount of co2 in the wine at bottling will have a significant effect on the results. In general, laminar flow down the side of a bottle will supply more oxygen than bottom filling, so during racking for example, the old textbooks suggested that method as a compromise between bottom filling and splash racking. Flow down the side provides increased surface area over bottom filling, but laminar flow is in layers and mixing does not occur between the layers of liquid. When you splash fill, the liquid is constantly mixed with air bubbles, and the bubbles break and remain suspended for some time. There are many other variables involved, I don't really know the answer, you would have to fill bottles and test for dissolved oxygen to know for sure.


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## fafrd (Apr 22, 2017)

vacuumpumpman said:


> @ fafrd
> I was assuming that you wanted to fill from the bottom according to one of your comments, my mistake.
> 
> I can fill a 750 ml bottle of wine under vacuum in approx 15 seconds, using the Allinonewinepump being that it is under vacuum - and air is made up of 21% of oxygen. I know for certain that there is less contact with oxygen due to the bottle being under vacuum.Especially considering I sulfite them and turn them upright as soon as I am ready to bottle.
> ...




Thanks. No downside to down-the-side filling (pun somewhat intended ) but if it is too expensive/complicated to achieve versus splash filling, probably not the end of the world...


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## fafrd (Apr 22, 2017)

stickman said:


> At this point, any discussion of what method would supply more oxygen to the wine is just speculation or theory. The amount of co2 in the wine at bottling will have a significant effect on the results. In general, laminar flow down the side of a bottle will supply more oxygen than bottom filling, so during racking for example, the old textbooks suggested that method as a compromise between bottom filling and splash racking. Flow down the side provides increased surface area over bottom filling, but laminar flow is in layers and mixing does not occur between the layers of liquid. When you splash fill, the liquid is constantly mixed with air bubbles, and the bubbles break and remain suspended for some time. There are many other variables involved, I don't really know the answer, *you would have to fill bottles and test for dissolved oxygen to know for sure.*



That probably goes beyond the level of investment I'm prepared to make into this question. If the assumption that the mechanisms underlying outgassing and aeration are related, comparing laminar outgassing to splash outgassing to see which gets fully degassed first could be an experiment I'll get around to trying.

Splash filling is simpler than laminar filling - it requires a straight filling tube while laminar filling requires the filling tube to be bent or the flow to be diverted to the sides of the bottle in some way.

If the only downside to splash filling is more foaming, that's a trade-off I'd be prepared to consider. 'Bruising' the wine might be another story but it sounds as though that is a vinyard myth .


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## vacuumpumpman (Apr 22, 2017)

fafrd said:


> Thanks. No downside to down-the-side filling (pun somewhat intended ) but if it is too expensive/complicated to achieve versus splash filling, probably not the end of the world...



I think you should try it with some commercial wine and rebottle it with your idea - I believe you will find out that is why the commercial vacuum bottle fillers fill along the side, rather than straight down.


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## fafrd (Apr 22, 2017)

vacuumpumpman said:


> I think you should try it with some commercial wine and rebottle it with your idea - I believe you will find out that is why the commercial vacuum bottle fillers fill along the side, rather than straight down.



That's an interesting idea - thanks.

I was planning on testing with water but that's not going to let me understand how much difference there is with foaming and whether it's a problem for consistent fill level or not...


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