Questions about Milkshake IPA recipe- mouthfeel&Puree Addition

[Miles_1111]

I have brewed a Milkshake IPA without adding any fruit or puree yet.
Pale Malt 81.2%
Munich Malt. 5.5%
Flaked Oats 9.2%
Lactose 4.1% ( about 11g/L)

Kveik Yeast
Mashing at 66 degree C
6.6% ABV, 30+ IBU

Two questions:
1. The taste of the beer is OK, but it didn't give me the soft, smooth mouthfeel, at least not enough, also did not have enough milk flavour. Should I increase the proportion of flakes oats and lactose? If so, to how much? Or maybe adding wheat and rye will help?
2. The next version I want to add puree, like 100g/L, mango or passion fruit puree. Should I add it at the beginning of fermentation? If so, how to calculate the amount of sugar in the puree transfering into ABV? Or that amount of increase does not need to be counted?

 

[VikeMan]

I have brewed a Milkshake IPA without adding any fruit or puree yet.
Pale Malt 81.2%
Munich Malt. 5.5%
Flaked Oats 9.2%
Lactose 4.1% ( about 11g/L)

Kveik Yeast
Mashing at 66 degree C
6.6% ABV, 30+ IBU

Two questions:
1. The taste of the beer is OK, but it didn't give me the soft, smooth mouthfeel, at least not enough, also did not have enough milk flavour. Should I increase the proportion of flakes oats and lactose? If so, to how much? Or maybe adding wheat and rye will help?

For mouthfeel, mash at a higher temperature and (perhaps) for a shorter time. This will also decrease attenuation, so if you want the same ABV, also use more grains, which in itself will also increase mouthfeel. You can also increase the lactose for mouthfeel and sweetness. But it's never going to taste like milk, because lactose is a sugar, not actually milk. (Milkshake IPAs get that somewhat misleading name because of their mouthfeel/body and fruit (or other) additions.)

2. The next version I want to add puree, like 100g/L, mango or passion fruit puree. Should I add it at the beginning of fermentation? If so, how to calculate the amount of sugar in the puree transfering into ABV? Or that amount of increase does not need to be counted?

If you are kegging and will always keep the keg cold, and will not be doing any bottling/growler fills, you can add puree at packaging. In this case, the puree will add sweetness. Depending on the puree, there may be a small risk of clogging the keg's liquid post's poppet.

Otherwise, add the puree at/near the end of primary fermentation, either in the primary fermenter or in a secondary vessel. Regarding Gravity/ABV, you can determine/estimate the total soluble carbs, sugars, and water content of the puree, and do the math. I wrote an article about how to do this for the May/June 2021 issue of BYO magazine. It's middle school level algebra, but it's a bit tedious. Instead, you could download FruitCalc, a spreadsheet that takes the gravity and volume details of your base beer and allows you to add amounts of various fruits (including purees like mango and passion fruit) from dropdown lists, estimating the impact of the fruits on OG, FG, and ABV. You wondered whether the amount of "increase" needs to be counted... Note: depending on the base beer and the specific fruit(s) added, ABV may actually decrease. If you find an online calculator that doesn't want to know anything about your base beer and/or always predicts an ABV increase (regardless of the beer and the fruit(s)), don't believe it.

FruitCalc can be downloaded from -> Google Drive <- or -> DropBox <

 

[Gilbert Spinning Horse]

The best way to ramp up the mouthfeel is to follow a raw ale proceedure. I'd increase the oats too, I use about 20% flaked oats myself.

 

[Miles_1111]

For mouthfeel, mash at a higher temperature and (perhaps) for a shorter time. This will also decrease attenuation, so if you want the same ABV, also use more grains, which in itself will also increase mouthfeel. You can also increase the lactose for mouthfeel and sweetness. But it's never going to taste like milk, because lactose is a sugar, not actually milk. (Milkshake IPAs get that somewhat misleading name because of their mouthfeel/body and fruit (or other) additions.)

I am afraid higher temperature ( above 66C) will add more sweetness, since too sweet is one common flaw when brewing NEIPA or milkshake IPAs? I had NEIPE mashing at 67 or 68C which was too cloying. High mashing temperature will help with body for sure, but will help mouthfeel as well?

 

[VikeMan]

I am afraid higher temperature ( above 66C) will add more sweetness, since too sweet is one common flaw when brewing NEIPA or milkshake IPAs? I had NEIPE mashing at 67 or 68C which was too cloying.

If you are worried about too much sweetness, remove/reduce the lactose. It's adding more sweetness than 1-2 degrees of temperature.

I had NEIPE mashing at 67 or 68C which was too cloying. High mashing temperature will help with body for sure, but will help mouthfeel as well?

Yes, because dextrins and medium length proteins affect both body and mouthfeel. Mouthfeel is really (largely) just the way body is perceived. There are also some non-body related components to mouthfeel, such as carbonation ("prickliness") and astringency, but I assume those are not what you'e looking for. Also, "slickness." If that's what you're after, add more flaked oats.

 

[Miles_1111]

If you are kegging and will always keep the keg cold, and will not be doing any bottling/growler fills, you can add puree at packaging. In this case, the puree will add sweetness. Depending on the puree, there may be a small risk of clogging the keg's liquid post's poppet.

Otherwise, add the puree at/near the end of primary fermentation, either in the primary fermenter or in a secondary vessel.

In that case, this is quite a difference of adding puree between kegging and bottling. The former is sweeter than the latter, as the sugar is not fermented due to cold temperature, right?

Another question is that how much of fermentable and unfermentable sugar in the puree? Say if I add near the end of primary fermentation, does the puree can add sweetness to the beer due to the unfermentable sugar left? Or it can only increase the fruity or sour flavor, since all the sugar is consumed by the yeast.

 

[VikeMan]

In that case, this is quite a difference of adding puree between kegging and bottling. The former is sweeter than the latter, as the sugar is not fermented due to cold temperature, right?

Yes, there would be quite a difference in sweetness. In the case of adding the puree at packaging, cold temps will severely slow (if not completely halt) fermentation of the fruit's sugars.

Another question is that how much of fermentable and unfermentable sugar in the puree? Say if I add near the end of primary fermentation, does the puree can add sweetness to the beer due to the unfermentable sugar left? Or it can only increase the fruity or sour flavor, since all the sugar is consumed by the yeast.

I wouldn't count on any discernable sweetness from fermented puree, assuming you let fermentation go to completion. The sugars in the puree are basically 100% fermentable. Fruits (and their purees) also contain some unfermentable carbohydrates, but these aren't really sweet. And AFAIK, no fruits contain any significant amounts of maltotriose, which is the sugar that's typically only partially fermented by beer yeasts.