When it comes to color, the life of a beer brewer is very simple. Most malt catalogs have the color-coding mentioned on their packs (CoA- Certificate of Analysis). A simple mathematics with a weighted average of the color of its constituents is all it takes to predict the color of the beer. It can be expressed in the SRM (Standard Reference Method), Degrees Lovibond, or EBC (European Brewing Convention). There are minor technical differences between the three reporting conventions. However, a color card or a photo-based mobile app can predict the darkness of the beer to a great accuracy. Higher the number, the darker the beer is.
Sometimes improper mashing, charring of the grain (kettle caramelization) can alter the color too. Certain fruits, herbs, and cocoa powder can also impart color and needs to be accounted for. But apart from these, a simple weighted average using an excel file based model is all it takes to predict the color.
Wine makers need to be much more vigilant. The red color comes primarily from the tannins. Tweaking the contact duration with the grape skin is the traditional way to infuse colors. However, fruits are difficult to standardize. Each fruit harvest would have different levels of sunshine, different soil, and humidity conditions and will produce variations. Furthermore, colors like purple and deep red are susceptible to changes in pH. Oxidation and oak tannins can also alter the color. It is best to keep some Calcium carbonate (CaCO3 removes oxalic acid and neutralizes acidity) to increase the pH and some acid blend (mixture of tartaric, citric, and malic acids) to reduce the pH. Conducting a few tests using a basic titration is sufficient, followed by standardizing the pH and total titratable acidity for the rest of the batch.
But what about body & mouthfeel?
When it comes to the body of the brew, the tables turn. The body in wines come primarily from the fruit. Adding more fruit pulp (using little or no water) is the simplest way to add more body. Wines made from packaged juices or concentrates have too little pulp and should be avoided. Adding raisins is another hack, being made from dried grapes, they can help improve the mouthfeel. Essentially desiccated grapes and fruits increase the fruit mass content per liter of beverage making it less watery. In white wines especially champagne lactose improves the mouthfeel and residual sweetness (reducing any harshness if any too.) You can experiment a bit with unfermentable sugars like Crystal malts, lactose which improves the mouthfeel and make your wine and beer taste less watery.
Beers get their body primarily from the unfermentable sugars. Adding specialty malts (like crystal), and high-temperature mashing can help increase the body. While adding amylase enzymes, corn, rice and honey/ sugars to the mash will thin out the beers. English style ales/ stouts have a heavy body while American style beers and lagers are very thin. So there is no global standard on how much-dissolved solids should be there in a sample of beers and wines.
Beware of micro-filtration and excessive use of fining agents. They can strip the beverages of the body and make them too watery.