Petnat?

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Ignoble Grape

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It's harvest time on the Central Coast! Every winery is full-on harvest here. Went out to a winery yesterday to pick up some Pinot Noir - the winemaker had me help bottle some Petnat. This one was new to me. He recommended I try making some.

Other than needing to watch SG carefully, and a special bottle capper and bottle caps, seems like a really easy way to make sparkling wines.

Anyone tried this before? How hard is it really?
 

cmason1957

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I have to admit I had never heard the term before. I did find this:

"This genre of sparkling wine, now known as pétillant natural, or pét-nat, is made by a method so old that the French term for it is “methode ancestrale.” It’s most likely how the original sparkling wine was made, however many centuries ago that was, although that was almost certainly an accidental creation."

https://www.nytimes.com/2018/03/08/dining/drinks/wine-review-petillant-naturel.html

No words there on exactly how to pursue making this kind of wine.
 

salcoco

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from the description it looks like fermenting wine is placed in a champagne bottle, when regimentation is complete let it clear and drink. the fermenting wine add the carbonation. if it clear or not still drinkable?
 

bathman

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I'm going to try my hand at some pet nat this year. Whilst it all involves finishing primary fermentation in the bottle to get the bubbles, there are various schools of thought on other aspects of it e.g. adding (or not adding) sulphites and whether or not to disgorge. I think traditionally to stay as 'natural' as possible you would not disgorge, and leave the yeast sediment in the bottle, which is why a lot of pet nat is cloudy. For the same reason you wouldn't normally involve any filtering when making pet nat.
 

Ignoble Grape

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This is what I got:

Bottle it at 1 brix. Do not bottle at more than 1, or risk explosion. It's like Monty Python and the Holy Hand Grenade. 3 is right out. Less than 1 won't work.

The winemaker I spoke to doesn't disgorge, making it as natural as possible. It doesn't come out clean, which I could see a natural appeal to for a certain market.

Not sure about MLF, or if there's a shelf life. I'll have to find out more...
 

bathman

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I was wondering if anyone has any ideas about working out correct point to bottle fermenting wine for 'pet nat' style wine?

I have seen the 1 brix mentioned a few times, presumably that means adjusted brix as opposed to the brix you would get from a refractometer? (which would be affected by the alcohol %).

According to a refractometer conversion calculator, with a starting brix of 17.5 when the refractometer reaches 7.4 Brix this would give me an adjusted 1 Brix actual measurement. Does that sound about right?

From what I can glean online, you would want to bottle at around 16g/l residual sugar in your wine in order to achieve ~4 atmospheres of pressure. Does anyone have any idea how to calculate residual sugar using specific gravity??
 

Ignoble Grape

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I was wondering if anyone has any ideas about working out correct point to bottle fermenting wine for 'pet nat' style wine?

I have seen the 1 brix mentioned a few times, presumably that means adjusted brix as opposed to the brix you would get from a refractometer? (which would be affected by the alcohol %).

According to a refractometer conversion calculator, with a starting brix of 17.5 when the refractometer reaches 7.4 Brix this would give me an adjusted 1 Brix actual measurement. Does that sound about right?

From what I can glean online, you would want to bottle at around 16g/l residual sugar in your wine in order to achieve ~4 atmospheres of pressure. Does anyone have any idea how to calculate residual sugar using specific gravity??
Really curious about this, too.
 

Trick

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I did petnat several times so far. Those batches made my fastest bottling record. One batch took only 7 days from pitching yeast to bottling!

My approach is to bottle when the SG is 0.004 or 0.005 higher than the FG of complete dryness. This give about 3 atm of pressure.
It is tough to estimate the FG of dryness, however. I typically split a batch of must into two. One is made as still white and will start first while the other must stays in the fridge without yeast. Once the first fermentation is done, I got the FG reading and start the second one with EC1118 until SG=FG+0.004 (0.005). An accurate hydrometer helps to get the good reading. The challenge is to catch the exact point to stop primary fermentation. It is hard to maintain consistency between batches. Some batches were over-pressured and made a big fountain when I cracked open the cap while the others were perfectly fine.

Sometime, I would try cold crash for a week or so after primary fermentation to allow the sediment to settle at low temperature and then bottle the supernatant. This helps to make the wine clear.

Next time, I will try dosage with 10g/L of sugar after reach complete dryness for more accurate control of pressure.
 

sour_grapes

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I typically split a batch of must into two. One is made as still white and will start first while the other must stays in the fridge without yeast. Once the first fermentation is done, I got the FG reading and start the second one with EC1118 until SG=FG+0.004 (0.005).
Hey, @Trick , that is a good, uuuhhh, trick! Very clever.
 

bathman

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Well, it confirms that 1 brix is the correct figure to achieve as that gives 10g/l sugar, but it doesn't really give any clue as to how you work out when you have 1 Brix left. I'm sure there must be a way as plenty of people make pet nat!

Some batches were over-pressured and made a big fountain when I cracked open the cap while the others were perfectly fine.
From some video's I've seen sometime Pet nat can cause big fountains due to the sediment etc that gets left in the bottle (in particular with tartrate crystals) which causes lots of nucleation points causes lots of bubbles.

Think I am going to bottle this weekend, not far off being dry for all of my wines, may add a few grams of sugar per bottle to make sure I get some sparkle
 

bathman

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So, I have now bottled some Rose and Red 'Pet Nat' style (really 'ancestral method' rather than Pet Nat), bottled at 1.000 SG so will see how it goes. Will probably open a bottle in a month to see if it has become carbonated and check if the wine is dry.

Found this website useful, it follows the production of some pet nat someone has made on a small scale, including some great videos on the gushing nature of pet nat if you don't disgorge! http://pet-nat.com/astrobunny/making-it/

IMG_20191119_232900.jpg
 

stickman

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I don't make carbonated wines so naturally I'd be a little nervous, but I also understand that you'll never learn if you never try. It would be nice to have a Schrader valve on one of those bottles to occasionally check pressure. Some people use a PET soda bottle to check for carbonation based on how solid it feels. Keep us posted.
 

Sailor323

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1) Méthode champenoise. I have done this several times. Ferment base wine to dry, add sugar watch for fermentation overnight (may be necessary to add a champagne yeast), bottle using either champagne corks and hood or crown caps. This is a standard way to bottle beer but you don't have to wit overnight to verify fermentation. 2) I don't disgorge, but if you leave the wine too long it will become yeast bitten.
 

Ignoble Grape

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@Adam Beck I just tried this with a strawberry I started over the new year. Saved strawberries through the summer in the deep freezer. I got two 750 ml bottles going, bottled @ 1 brix. I use scrounged bottles and was hoping for 6, but I learned that sparkling wine bottles have different size cap apertures - makes sense, but didn't figure that out until I'd filtered off and filled all 6 bottles. I'm a little concerned about pressure, just like @stickman mentioned. Would be great if there were a way to check on it. In the meantime, I've placed the bottles in their own special little tub in a corner of the garage. Just in case...

I did ask all of the friends and co-workers to save their sparkling wine bottles over the holidays. Also got a lesson on capper bells at the brew shop. Hoping to re-try this experiment in the fall with the actual grapes on a larger scale.
 
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