22 replies to this topic

[Fishrmn703]

I'm anticipating a hot year where the sugar levels rise quick. Is like to let the clusters hang for a longer time to allow pH to increase and flavor to develop. Without watering down the berries flavor, can you irrigate slightly once brix starts approaching higher levels to allow flavor and pH to catch up? Will this lower the quality/concentration in the berries?

Thanks,

Joe

[gregorio]

I'm anticipating a hot year where the sugar levels rise quick. Is like to let the clusters hang for a longer time to allow pH to increase and flavor to develop. Without watering down the berries flavor, can you irrigate slightly once brix starts approaching higher levels to allow flavor and pH to catch up? Will this lower the quality/concentration in the berries?

Thanks,

Joe

It is all about balance. If you get to 30 Brix before your acids drop and flavors arrive, what is the point? You have to water to keep everything in balance. WHEN and HOW MUCH are the keys. Too early in the berry development stage (post flower-pre veraison) and your berry size could get too large. This might prevent you from reaching your desired flavor. Too much at anytime and the vine could go back into growth mode.

[Fishrmn703]

Seems like watering at key times can make a huge difference in berry development, or lack of development. Will watering as brix levels rise actually drop the levels back a couple brix or will it slow further increases in brix? Or is it that once brix rises there aren't ways to manipulate it back down to allow the berry to further ripen and flavor to catch up.

[gregorio]

Seems like watering at key times can make a huge difference in berry development, or lack of development. Will watering as brix levels rise actually drop the levels back a couple brix or will it slow further increases in brix? Or is it that once brix rises there aren't ways to manipulate it back down to allow the berry to further ripen and flavor to catch up.

Yes you can manipulate Brix a little bit but you have to stay ahead of it. You have to anticipate and start the water before your sugars hit your target. You also have to keep the vine from going too far into shutdown, Trouble is that when you see the vine needs water it is too late.

[Tomer1]

Is this where fancy vine-water status measurment equipment come to play?

[Fishrmn703]

Sounds like it takes quite a bit finesse and being able to tell subtle clues regarding vine water needs. I'm having enough trouble figuring out when to start irrigating post berry set. Having equipment to help measure the vines water would be helpful, but sounds too expensive for me. I guess this is where experience cones in handy.

[gregorio]

Is this where fancy vine-water status measurment equipment come to play?

They can be helpful but after a while I would think experience would be just as good. Following the weather reports is essential too.

[gregorio]

Sounds like it takes quite a bit finesse and being able to tell subtle clues regarding vine water needs. I'm having enough trouble figuring out when to start irrigating post berry set. Having equipment to help measure the vines water would be helpful, but sounds too expensive for me. I guess this is where experience cones in handy.

They will only tell you how much moisture is in the soil at a certain depth. Roots are pretty deep and wide spread. You will need to map that information to the vine's true needs at that point in time. Also, it wil vary from year to year depending on the amount and timing of rain.

A meter that indicates that there is x% moisture at y date means nothing unless you are looking at the vines constantly and taking into consideration how much rain fell last season and when it came down.

[Fishrmn703]

I guess it's those season specific factors and choices that make each vintage unique: )

[Tomer1]

Interesting stuff

[kendall]

It sounds like a vine diary needs to be kept on all the variables so that you can plot what is going on year over year and day over day. Sounds like a software app should be built for this, it would make it a lot easier to graph it and see whats going on.

[Wade's Wines]

I picture, correctly or not, the grapes as a baloon with sugar water inside. When they get a good drink of water there's the same amount of sugar but more water, so lower Brix in the grape because that ratio changed.

Greg, can you cause grapes to hang longer by keeping them watered later into the season? My Catawba is ready to fall off the vine at 20 Brix in August, and I still have months of growing season ahead. How can I get them to hang and develop longer?

[bigadamsoy]

I picture, correctly or not, the grapes as a baloon with sugar water inside. When they get a good drink of water there's the same amount of sugar but more water, so lower Brix in the grape because that ratio changed.

I don't think this is entirely accurate. Water doesn't go directly from the roots to the grapes. It's much more complex than that. Lots of growers find they get good results by continually irrigating throughout the ripening period without swelling the grapes up with water. In fact, I think it's pretty hard to make the grapes grow a whole lot after veraison, no matter how much water they get.
I think that a while back somebody posted a link to a video of Marquis Phillips of Molly Dooker talking about using frequent watering to extend the ripening season and achieve more flavor. I don't know if this is a case of viticultural bullshit or real results, but it's worth looking into.

[gregorio]

That is one way to look at it but the whole process in much more complex. Brix drops after watering are only replacing the water lost to dehydration. This usually means the vine is stealing water and that the fruit is ready to harvest whether it has reached YOUR desired numbers/flavor or not.

Assuming an otherwise healthy vine and average climate conditions, water can be added in sufficient amounts to slow brix accumulation. The water can extend the time the vine stays in the the ripening stage and forestall the moving into shutdown even though sugar accumulation is almost stopped. How long depends on a lot of factors like how long the vine stayed in all the previous stages and how close to shutdown the vine is when water is applied. Carbohydrate stores and crop load play an important role too. Careful water management all year is required to get the most from your vines. In general adding excess water at these times has the following effects.

Break through cluster = more shoot growth
Cluster through set = more shoot growth and longer stems or even shoulders
Set through veraison = more shoot growth plus laterals and larger berries
Veraison through shutdown or more likely senesence = some shoot, lateral and berry growth but less sugar accumulation

Other things that you can "manage" all year along with water inputs are Potassium additions, leaf and canopy thinning, cluster or shoulder thinning, etc. We usually have very wet spring conditions so we can't control the huge canopy growth and often multi-shouldered clusters. So. by veraison, we are trimming shoulders or cutting the bottoms off of clusters and spraying Potassium as determined by tissue samples. If the weather remains warm post veraison, we begin watering to keep the vine ripening all the way through the warm October we get. If we did not water, the vines would be in shutdown by mid September and the fruit would never get over 22 Brix.

[gregorio]

BTW, just because you can keep a vine in the "ripening" stage does not mean it will continue to accumulate sugar. Some varieties seem to top out at a certain number and won't go any higher no matter what you do.